(This character is from the unparalleled @nobody33333333's fic "S.O.S."! And, a quick note to the beautiful author, feel free to smack me down if anything I say is wrong, this is purely the speculative product of me R O T A T I N G / "Microwaving" this man for the last forever)
He really likes the colour lavender, and incorporates it into his clothes wherever he can. His most common trick is a necktie, and his wife helps him plan his outfits so that they don't clash too bad, because he'll just wear whatever and then throw the tie on regardless.
He is really good at cleaning and sewing! Honestly, this man could run a dry cleaners, partially because he tripped into so many puddles that it just became practical, and partially because he enjoys it! (This has nothing to do with the awesome detail of him making S. Q. the stuffed bird shush your mouth)
But anyways, more on that stuffed bird: I like to think that he made it out of old clothes (so it smelled like them and probably added to the comfort), maybe one of his shirts and a lovely patterned scarf that belonged to his wife, so that he could get it as accurate to the bird it was modeled after as a stuffed toy can be.
There was definitely at least one time that he took his wife out on a picnic and made her a flower crown.
I know in my soul that his man loves Sandpipers. His favourite is probably the Spotted sandpiper. I mean, have you seen the things? Their little feet are so big! They have such fluffy, round, little bodies and sticks for legs!
He keeps a notebook of birds that he'd like to see in the wild, ranging from a Eurasian magpie to a shoebill to a hooded pitohui (That one oriole-related bird that has neurotoxins in its feathers)
He really likes patterns, being in neurology, so Fibonacci spirals, fractal geometry, tessellation, all the things.
He enjoys writing poetry, even though it isn't his strong suit, and would leave little goofy notes in couplets around every once and a while for his family. (I like to imagine that he and Curtain would play rhyming games on rare occasions)