A/N: Something that popped into my mind, while I was re-reading 'Harry Potter and the Goblet of Fire'. Exact quote at the end.
I have no beta; English is not my first language. Please don't stone me.
None of this belongs to me, otherwise I would not bother with school.
The Grey Nightshirt
There had never been any doubt in Hermione Granger's mind that she was anything but normal. Perfectly normal.
Despite her cleverness - which was just as much of a curse as it was a blessing - Hermione mostly thought herself to be quite boring.
She was no beauty. Her hair was unruly and thick, impossible to get straight, and her hair and eyes had the same boring shade of brown.
The only talent she possessed - for she could neither dance, nor sing, nor draw or write poetry - was her ability to quote "Hogwarts: A History" down to the last footnote.
But after being laughed at - in a friendly way, but laughed at, nevertheless - by Harry and Ron, the only real friends she had, Hermione had given up on that one talent of hers.
Since she was so very normal and boringly so, Hermione had always thought that she would live a well-structured life, just like her parents did. A normal life. An easy life.
She had been sure that she would one day do her final exams at Hogwarts - which she did - then find a safe and if possible well-paid job in which she could bring her few talents and her affinity of wanting to free all mistreated magical creatures to good use - which she did; the Department for the Regulation and Control of Magical Creatures had never had a more ambitious employee - and then maybe someday find a nice, clever and funny man she could introduce to her parents without having to be embarrassed and then maybe marry that one guy. At the end of the war, the fight against Lord Voldemort, Hermione was positive that Ron was supposed to be that guy that was missing in her imagination of a normal life. After the final battle she could almost picture herself being married two Ron, having one, maybe two kids, and being perfectly content leading a normal and easy life with him.
How Hermione suddenly ended up wanting a not so normal life, with a not so normal job and a not so normal man, she wasn't sure.
She wasn't sure when the house she always dreamed of living in changed from a family-friendly one to a smaller one with a very own Potions Lab in the basement.
She wasn't sure when she realized that trying to save the House Elfs from enslavement was an impossible task and she instead wanted to search for an improved Wolfsbane Potion - preferably one that would not taste vile and have any aftereffects.
And Hermione was completely at loss when she asked herself when that normal guy in her imagination of a normal life changed from an Auror-to-be with red hair to a dark and unsociable man with shoulder length, jet-black hair.
What even more surprised Hermione was that she suddenly found herself quite fond of her former teacher and somehow craving for his presence, his company even.
SSHG
Even more surprising the seventh anniversary of Voldemort's downfall and the yearly Ministry Ball found Hermione wearing her favorite blue dress, her hair up in an elegant, yet simple knot, with only a few curls framing her happy face, and waiting at the doors to the gigantic Ministry Ballroom for just that Potions Master.
When Severus Snape arrived, wearing his usual black attire, Hermione felt yet again how even his mere presence still made her heart jump.
„You look radiant, my dear", the dark man said and lifted Hermione's right hand to his lips to gently press a kiss onto her knuckles.
As much as she tried to, Hermione could not help but blush and Severus allowed himself a small smile, seeing what affect he still had on the witch.
„You don't look too bad yourself", Hermione finally said and then linked arms with the dark-haired man.
Together the couple stepped into the Ballroom, Hermione smiling at people she knew, Severus nodding at a few familiar faces at best.
After being together for little over five months - four of which being the number one topic in The Daily Prophet and The Witch Weekly - , their appearance did not cause mayhem anymore as it used to. No former students of classmates, no co-workers of ex-colleagues turned around to stare at them anymore or talk behind their backs. Most of the magical community had gotten used to the fact that Hermione Jean Granger and Severus Snape were no romantically involved.
Most witches and wizards anyway, not counting Molly Weasley, who was still rather angry that she didn't get Hermione as a daughter-in-law, but some blonde, part-Veela bimbo Ron had met at a Cuddley Cannons match, and Hermione's supervisor in the Department, who was pissed that he lost his best employee to a Potions Master and his basement laboratory.
However the rest of Severus and Hermione's friend, mostly of course Hermione's friend, where quite glad that Hermione had someone to talk academic to.
But five month of relationship and Hermione still did not know half as much about Severus as she wished to.
They had, for example, never spent a night together, thus far. It wasn't so much about the sex for Hermione, she just wanted to know if waking up to him felt as good as dancing with him, or kissing him.
And there were so many small details she wished to know: His favorite dish, what his favorite ice cream had been when he was young, why all of his clothes were black - that was a secret Hermione was perhaps most curious about. After five month she still hadn't seen Severus wear anything but black. Some things like his old brewing coat, looked worn and battered, but they were still black.
After the end of the ball, however, as Severus put his arm around her waist to Apparate her home as he always did, Hermione was sure that he would kiss her goodnight and then politely decline her offer of coffee.
When the spinning of Apparation ceased, Hermione found herself standing in front of Spinner's End. She turned to look at Severus, but before she could utter a word he spoke.
„Would you like to come in?", he asked and as he met her gaze, Hermione saw something like uncertainty in his black eyes. Those black depths she had come to love, but was still unable to read.
Smiling up at him, Hermione nodded and could see the tenseness leaving his body.
„I would love to."
SSHG
A few hours later Hermione lay in Severus' bed - which was quite comfortable -, wearing the black shirt he had worn that night.
As he stepped out of the loo, which lay adjacent to the bedroom, Hermione's eyes grew big and a big grin spread across her face which became bubbly laughter at Severus confused look.
„What is it?", he asked, brows furrowed.
It took Hermione a few moments and a few futile attempts to stop laughing before she could answer.
„I have been wondering about this for ages!", she finally managed to say between giggles, „It's grey, Severus! Your nightshirt is grey."
It was certainly a step further, though no major one, but Hermione was more than happy to finally have solved at least one mystery entwining Severus.
Severus in the meantime never quite understood what it was about his grey nightshirt that nearly drove his witch into insanity. Nevertheless he did not cease to wear the few grey shirts he owned during nighttime - just to see Hermione smile, whenever he pulled it on.
And after that night, seven years after Voldemorts - or Voldie, as many people like to call him nowadays - defeat, Hermione was more often than not to be found in Spinner's End.
A/N2: At the foot of the stairs stood the only person that could make Harry's situation worse - Snape. He was wearing a long grey nightshirt and he looked livid.'
The Egg and the Eye - Page 511, Harry Potter and the Goblet of Fire
I just HAD to do a One-shot to this. Severus in a grey nightshirt. Wonders never cease!