They're totally comfortable, always fashionable and can be super cool.
That's why we like them... Right?
So, in honor of T-shirt weather, here are 8 important things — good and bad — that you might want to know about this beloved article of clothing.
1. F. Scott Fitzgerald — you know, the author of "The Great Gatsby" — is credited with naming the T-shirt.
Hold up a T-shirt, and it's easy to see the letter shape it forms. Fitzgerald thought so, too — he's credited with the first written appearance of the word "T-shirt." In his 1920 novel "This Side of Paradise," F. Scott Fitzgerald described a character's wardrobe as "provided with 'six suits summer underwear, six suits winter underwear, one sweater or T shirt, one jersey, one overcoat, winter, etc.'"
2. There's a Guinness World Record for the most T-shirts worn at once, because of course there is.
When there are world records for the largest hockey stick (big ups to Duncan, B.C., Canada) and most eggs crushed with the head in 30 seconds, there absolutely has to be one for wearing the most T-shirts at the same time.
The holder of this very specific title as of this writing is Sri Lanka's Sanath Bandara, who wore 257 T-shirts at once to win it in 2011. Altogether, the shirts weighed more than 200(!) pounds.
3. 9 out of 10 Americans are probably wearing a T-shirt right now.
There's a matching T-shirt for every one of those hoodies. Image via iStock.
According to a 2013 survey by CustomInk, 95% of Americans wear T-shirts with 89% of them wearing one at least once a week.
4. James Dean and Marlon Brando looked so good in T-shirts that it basically defined their early careers — and started the T-shirt craze.
Marlon Brando in "A Streetcar Named Desire." Image via Wikimedia Commons.
If you've seen the 1951 version of "A Streetcar Named Desire," there's probably one moment you remember most: Marlon Brando, standing in the rain in his ripped T-shirt, yelling for Stella. Ditto for "Rebel Without a Cause": James Dean, effortlessly cool, wearing a T-shirt and blue jeans lounging against a muscle car.
These visuals are iconic, and they helped make Brando and Dean into heartthrobs and superstars.Brando's T-shirt-wearing was particularly shocking because T-shirts were not meant to be worn on their own (they were called bachelor undershirts, meant to be worn under another shirt). But instead of hurting shirt sales, he boosted them big time.
5. Cotton — the most common ingredient in t-shirts — is a huge business.
Image by iStock.
In the United States alone, there are 35,000 cotton farms, employing about 170,000 people.
6. T-shirts take a lot of cotton to make. And even more water.
Making T-shirts is thirsty work. Image by iStock.
Most T-shirts are made completely or partly from cotton. America is the third-largest cotton producer in the world, harvesting almost 13 million bales, or 6.2 billion pounds, in 2015-16. For every acre of cotton harvested, fabric companies can make 1,200 T-shirts.
7. New shirts made from recycled cotton can make a big difference.
T-shirts made with recycled cotton look and feel identical to their non-recycled counterparts. There's one big difference: Their sale keeps tons of textile waste out of landfills every year.
8. Millions of T-shirts are donated at thrift shops every year. But even more end up in places like this.
Landfills are a depressing place for any object — let alone a favorite T-shirt that's a little past its prime. Many shirts will find their way to a new friend, but for those that don't, there's still a chance for a second life when you donate rather than throwing away ... just ask Macklemore.
All in all, there's a lot more that goes into making and selling T-shirts than might meet the eye.