Pretty much all I ever wear is T-shirts. Most of mine are black and geeky (Doctor Who, logos from my fantasy novels, cats, etc.). The few that aren’t black are gray or navy blue. I would say I have at least fifty of them–probably more.
I take good care of them, so they last a long time. I wash them in cold water and hang them to dry so they don’t shrink or wear out.
I made a conscious decision to simplify my life… by donating most of my khakis and polo shirts and colorful shirts and going with Basic Black. A pair of black jeans, which I can wear to work and no one thinks “Oh, he’s slumming in blue jeans.”
But I kept most of my black t-shirts. Most of them have meaning to me, and many are presents…
When relatives ask “What can I get you for Christmas?” I always say “Go to a fun concert and buy me a shirt. Black, all cotton if you don’t mind.” They get to see good music, I get a bitchin’ shirt.
So far, they’ve all been for bands I like, and have seen!
So I’m not fakin’ it… though I’ve decided seeing one band member is good enough.
So, got a great Crowded House shirt… luckily, about a month later, I got a chance to see Neil Finn touring with his family (so I could start wearing the shirt)!
Can’t afford to see the Eagles but that’s okay, I saw Timothy B. Schmit (with Poco) and Joe Walsh (with the James Gang) back in the 70s.
Mr.Wrekker gets many many tshirts thrown at him at places he’s worked. I think they must have cases of 2XT to get rid of. He’s a big/tall man who never wears anything but camo shirts.
So I sleep in all the big tshirts.
They have a variety of logos and equipment company’s ads. Some from weird sounding places.
Cheap jammies.
I forgot to mention my VERY FAVORITE t-shirt:
“I have been and always shall be your friend.”
signed by Leonard Nimoy! 
~VOW
Duuuuude, that is cool!
I’ve been comforted by this thread; I thought I was a “hoarder.” I’m glad I posted it with the poll. 
Tripler
So far, favorite t-shirt: Print of “Fat Man” schematics my wife bought me downtown.
Correction: I forgot about one. My newest one is the one I bought at the Brooklyn Superhero Supply Company last December. I suppose that falls under the category of nerdy shirts.
I have a collection of several hundred T-shirts. The oldest one is from a then-popular but now-defunct restaurant in my West Texas hometown, obtained in the mid-1980s. Still fits, sort of. Although I have graduated to 2XL, many of my XLs still fit. The ones that don’t tend to come from Asia, where even a 4XL would often barely pass for M in the West. I too collect them from my travels, organizations etc. I dislike T-shirts with mindless slogans like “Keep On Truckin’” etc.
Okay, that post inspired me to lose weight…
Although I have graduated to 2XL, many of my XLs still fit.
See, I have t-shirts that I haven’t been wearing because they’ve gotten a little tight (the first one I noticed, I thought it’d shrunken in the wash… ha!). So, if I can drop a dozen pounds or so, I’ll have a couple of cool t-shirts that fit. Black “obscure bands and places” shirts, of course.
(Like my favorite, from Bumbershoot. Huge, fun festival in Seattle; right in the city, in the park under the Space Needle. Full of music, spoken word, comedy and even lectures.)
So thanks for the inadvertent advice, Sam, and… keep on truckin’.
“When relatives ask “What can I get you for Christmas?” I always say “Go to a fun concert and buy me a shirt. Black, all cotton if you don’t mind.” They get to see good music, I get a bitchin’ shirt.”
That works except if your relatives are too old or musically daft, in which case you could wind up with a lovely Neil Diamond t-shirt.
I like Reverend Horton Heat t-shirts, but some aren’t terribly work-safe.
https://poshmark.com/listing/The-Reverend-Horton-Heat-tshirt-5eb7fb7c180136482c3394e4