My Winston Byrd Headcanons:
She was a lot more of a mellow person before being locked up. Though he was still rather excitable, Winston had far better of a hold on his emotions back then. Especially their temper. Some people would've even described her as gentle.
They were always fascinated by toons and their culture. Winston spent a lot of time researching it, both for work, and on her own time. (In fact, it was this fascination that led her to take this job in the first place.) Of course, this interest didn't necessarily indicate any real respect for the toons, and despite his efforts, its attempts to emulate their mannerisms were clumsy at best.
Winston's hobbies included bowling and whittling. He actually bowled competitively, and even won a few awards for it. (Fun fact, this hc spawned from a joke I once made about freeing Winston and taking her to various places, including the bowling alley. It has since been enshrined into my beliefs.) These days, Winston can sometimes be found sitting in the dungeon and carving figures with their knife and whatever happens to be laying around. (Usually, they're of people. Perhaps ones he used to know.) Of course, any skill she once had in this is undermined by her shaking hands.
He will eat just about anything. In my headcanons, cogs can digest anything combustible, but some things are much more healthy and pleasant to eat than others. But Winston's learned not to be picky. Dirt, wood, leftover gags, it doesn't care. If he were to be reintroduced into society, he'd have a lot of table manners to relearn.
Other cogs tended to regard him as being endearingly weird. They found Winston's interests a little strange, and found it especially odd when she'd let some toony phrase or another slip into their speech, but its demeanor was charming enough that most people just saw it as an interesting quirk. Nowadays though... if a cog were to meet it, they'd see her as frightening or uncanny. And/or just plain tragic.
They don't really have a concept of time anymore. Winston's internal clock is pretty much busted, and the only lengths of time that exist in his perception are A Couple Minutes, and Basically Eternity. She knows her sense of time is fucked, but it's only half aware of just how bad it's gotten. Sometimes, a few minutes stretch into infinity, and sometimes, hours pass without him realizing.