1. After their first successful hunt together in over four years, Sam and Dean spent a quiet night alone in their hotel room, Dean unsure if he should ask his brother if he wanted to find a bar, Sam too proud to ask how it had been for the last four years without him.
2. One night after a particularly tough hunt, Dean was astounded to see Sam get smashed and start belting out REO Speedwagon lyrics during karaoke; he was starting to see for the first time the type of person Sam must have been at college.
3. For his part, Sam never forgot waking up at 2 AM to find Dean glued to a Star Trek marathon on some local station, or the look on Dean's face as Sam fell back into bed in a fit of laughter.
4. They were fighting over something stupid when Bobby came in and left a pie on the table; Dean was distracted instantly and Sam could hear Bobby chuckling halfway up the stairs.
5. Early on in a history class at Stanford, Sam answered a few too many questions about burial customs through time and quickly busied himself with his notes while everyone looked at him as if he was a freak.
6. An attempted stabbing as payback for the handprint-shaped scar on his shoulder, and a lifelong friendship was born.
7. Castiel wrestled with how to tell the archangels that Dean believed him less and less these days, and that even worse, he was finding his own beliefs wavering.
8. Castiel found himself confessing his own doubts in his mission to Dean, barely wondering why it felt so right to have someone who finally listened to him.
9. Castiel was more nervous meeting Sam – the abomination – than going into Hell; nothing surprised him more than when Sam only expressed gratitude and awe at Castiel's role in bringing Dean out of Hell.
10. After their isolated childhood and three years spending every minute together, Sam and Dean thought no one could ever break into their duo, never counting on the arrival of a socially clueless angel who found his way into both their affections and somehow never left.
11. Dean had always considered anything non-human as the "monsters," he was forced to rethink his stance when he realized he'd never understand the crap humans put each other through, but found it easy to relate to a fallen angel and a vampire.
12. The decision to rebel wasn't so much a "decision," the look Dean gave him made it practically a given; no one had ever seen straight through Castiel like that before.
13. Wondering where Cas had gone, Bobby never expected to find him curled up on the bathroom floor looking miserable; apparently not even angels could just shrug off several hundred burgers in a day.
14. Dean rolled his eyes the first time he'd found a pure white feather in his car; after the release of the Leviathans, he could barely hold it together when he found the last one.
15. Dean was shocked when Heat of the Moment came on the radio and Sam practically destroyed the dashboard turning it off.
16. Bobby often considered cutting John Winchester out of his life the way so many others had, but he knew as long as Sam and Dean had no one else he never could.
17. Sam and Dean didn't expect Cas to show up on Christmas Day, but they couldn't help laughing at his confusion when he asked why there were so many angel figures on top of pine trees.
18. Over the years they'd gotten rid of everything they couldn't easily carry with them, but it was the proudest moment of Sam's life when he was finally able to take out his college diploma and hang it up in the Men of Letters bunker.
19. Dean never let him see, but the thought that Cas might not make it out of Purgatory with him haunted his every step.
20. The first night at Stanford Sam could barely sleep – he'd never shared a room with anyone but Dean before.
21. Once Sam left, Dean went to great lengths to hide the bags under his eyes – he couldn't get used to Sam not being in the next bed.
22. Dean never let his guard down in Purgatory; the only exception was when he needed to sleep, because he knew Cas would be watching.
23. Cas had thought he'd be glad to return to Heaven after stopping the apocalypse, but he found that once there, he mostly just wanted to be back on Earth.
24. Movie night was a sacred ritual, no matter where they were, every Friday, Sam and Dean would go see whatever movie was newly released
25. Ten years ago, anyone following him around uncertainly during Vegas week would have been unceremoniously dumped; this year, Dean was perfectly fine with Cas always half a step behind him.
26. The sign on the ICU said "immediate family only," and Cas started to leave dejectedly; he couldn't have been more shocked when Sam didn't skip a beat and insisted to the nurse that Cas was their brother.
27. Zachariah and Raphael subjected Castiel to hours of persuasion, but their suspicions that he was switching sides were absolutely correct.
28. "I'm trying to be useful," Cas said sadly as Dean stared in disbelief at the mess in the laundry room, "I guess I used a little too much detergent."
29. Every time he heard Dean pray to him, it was harder and harder not to go back and find him; only the thought that he was leading everything away from Dean let him keep going.
30. The whispers started the instant Sam and Dean walked into the bar, a known hunters' hangout, but everyone knew better than to go up against both Winchester brothers.
31. Sam always relished his turns driving at night because he always made sure Dean woke up to his least favorite music on the planet – easy listening.
32. "Don't you think you should wait for me before you run straight into a situation like that?" Sam asked amusedly as he watched Dean leave the day care center covered in paint and glitter.
33. "What took you so long?" Dean asked angrily the next morning when Sam finally showed up to post his bail.
34. Everyone assumed Crowley had chosen Cas because he was easily manipulated, which was true; but really, he'd recognized a fellow misfit from miles away.
35. Dean never admitted it, but he was always awed and a little scared when Cas unfurled his wings; it reminded him how otherworldly he truly was.
36. Sam was pleasantly surprised when he caught Cas perusing his bookshelf; he was even more surprised when Cas shyly asked him to recommend his favorite books.
37. Dean was the one who'd brought Game of Thrones in, Sam was responsible for Harry Potter, but their newfound obsession with Doctor Who was entirely Kevin's fault.
38. Channel-surfing at the hotel Dean had paid for; Cas came across a marathon of The Greatest American Hero and sat there mesmerized for hours until he had the entire theme song memorized.
39. Every young trainee heard Dean talking to himself at night; most of them never realized his prayers were more like letters sent to one angel who'd gone back to Heaven years before.
40. Crowley resisted the urge to groan every time he heard about some new apocalyptic plan; couldn't anyone see how this chaos would wreck everything?
41. Father's Day used to be a painful time for Bobby, bringing up memories of his father and his own childless state, but once Sam and Dean came into his life, he found himself able to take part in Father's Day each year with pride.
42. Cas was so disappointed he'd have to take a vessel; he'd felt such a kinship with Dean immediately he'd thought for sure that Dean would be able to perceive his true form.
43. Cas had never driven with a passenger before; the ride back to the bunker seemed endless with a morose Sam shivering in the seat next to him.
44. It occurred to Dean once that most people stopped believing in guardian angels as they reached adulthood instead of acquiring one.
45. As Dean reached out to calm to him down, it occurred to him that Cas could kill him with barely a second thought.
46. "You must have a guardian angel somewhere," the EMT said as he pulled Dean out of the rubble; Dean only grinned sadly and said, "I used to, years ago."
47. Their dad told Sam and Dean over and over that they could never trust anyone but each other; it was his actions more than his words that proved it to them.
48. They thought Cas would be better than Dean on an airplane; instead he gripped the handrails muttering, "This isn't how flight is meant to happen," making everything worse.
49. Cas spent hours trying to make the bunker's piano sound even remotely like the celestial harmonies he was used to, to no avail.
50. They spent longer explaining two-for-twenty appetizers to Cas than it took them to eat the food once it finally came.