Bleach belongs to Tite Kubo, which is not me.
May be small spoilers, but if you actually know who Sasakibe is, you are probably past them anyways.
Apathy
Yamamoto wonders if his lieutenant is truly as emotionless as he seems, but is too polite to straight out ask.
Baby
Inspired by something a lieutenant said, Sasakibe once tried to imagine his captain raising a baby. The result was spitting out his tea all over said captain.
Chuckle
Yamamoto has only heard Sasakibe laugh once. It was simple split second slip-up, and even with Sasakibe's embarrassment, it still took Yamamoto hours to figure out what it was.
Dead
Sasakibe once decorated Yamamoto's office with dead things to "get in the Halloween spirit". Yamamoto incinerated everything in the room. Including Sasakibe.
Excitement
Yamamoto will never forget when Sasakibe won his first fencing tournament. And he used to think Yachiru wanting candy was bad.
Fear
Yamamoto still doesn't know why he felt a small pang of fear when Sasakibe got defeated by Ichigo.
Guilt
Sasakibe was raised by Yamamoto since his very early stages of life. Yamamoto swears it's one of the worst mistakes he ever made.
Hot Spring
Sasakibe is the only one that will accompany Yamamoto in a hot spring; even if it is scalding and he faints within ten minutes.
Insubordination
The only time Sasakibe refused to follow Yamamoto's orders was when he was supposed to discuss an important topic with Kurostuchi. Yamamoto cannot really blame him for it.
Jump
Sasakibe is normally so quiet while in the office, Yamamoto has jumped a couple times when he unexpectedly started conversation.
Kill
Yamamoto wanted to kill the one who introduced Sasakibe to Western Culture, until said lieutenant slyly pointed out that Yamamoto was the one who forced him to go to the Human World in the first place.
Loyalty
Yamamoto wonders how Sasakibe wordlessly does anything he's told, when even he wants to go against Central 46 occasionally.
Morals
Yamamoto was quite shocked to learn that Sasakibe would attack the Spirit King if Yamamoto asked him to. Yamamoto is not sure what to think about the fact that Sasakibe is loyal to him, and to him only.
Near
Sasakibe is extremely close to captain level strength, but Yamamoto doesn't think he would survive a change in position.
Oxymoron
Sasakibe insists that he is unintelligent. He makes a good argument of it too.
Party
Sasakibe threw a surprise birthday party for Yamamoto. He soon had déjà vu of the Halloween incident.
Quick
Sasakibe wasn't exactly fast either physically or mentally, but when it came to following orders, he was second to none.
Respect
When the third seat accidentally mixed up their teas, Yamamoto flat out spit it out, while Sasakibe had enough respect to at least swallow-albeit begrudgingly-the drink he had in his mouth.
Strange
Yamamoto cannot understand why Zaraki irrevocably believes Sasakibe is evil.
Tower
Yamamoto refused to think about how the heck his lieutenant managed to blow up a tower with a tea boiler.
Upside down
Sasakibe once ended up hanging upside down from a tree after attempting to rescue a cat. That was one of the situations where Yamamoto truly had no idea what to do.
Vulture
Sasakibe was like the vulture of the 1st division; cleaning up whatever other members missed and doing whatever no one else did.
Weep
Yamamoto was beyond shocked to hear from Byakuya that Abarai said Sasakibe had started crying at a Sake stand.
X
Yamamoto cannot understand the simplicity of the English Alphabet, and wonders how Sasakibe can, and still think he is unintelligent.
Yearn
As much as Yamamoto likes to think he knows Sasakibe, he has no idea what would make him happier.
Zanpakuto
A much younger Sasakibe managed to trip over Ryujin Jakka once and ended up sending both himself and Yamamoto to the ground. He was smart enough to run when the captains started laughing.
Well… That was a bit… Yeah. Like, dislike, want more? Lemme know!