Binge watching it as I didn’t really watch it when it was airing the first time around.
I’d have to go with Sheldon. When I’m watching 4 or 5 episodes in a row, he annoys the crap out of me and so I turn it off.
The thing about this show is the characters have ALL the nerd stereotypes. They like Star Trek and Star Wars, They like comic books, retro gaming, D&D, awkward around women, etc. That’s just not realistic. Plus, Sheldon is clearly on the spectrum, but not only do they not recognize it, they make fun of it.
Eh, they also pretty much do whatever shuts him up the fastest, which is annoying. To compensate, they get to make fun of it.
A product of his rearing, I guess. Made a completely separate series about it.
When two of our grandkids were babies and would cry and cry, I would sing Sheldon’s song to them and they would stop crying. I taught my daughter the song cause she never watched BBT. It worked until they were about 18 to 20 months old.
*Soft kitty, warm kitty, little ball of fur, *
Happy kitty, sleepy kitty, purr, purr, purr.
It worked for Sheldon. 
[Sheldon] That’s only for when you are sick. Crying babies are not sick. [/Sheldon]