When you should not wear a t-shirt:
This piece of clothing shows every imperfection on your body. Humans are programmed to find symmetrical faces and things to be more attractive and so a t-shirt makes me look less attractive just because my body is not symmetrical and neither is yours. A t-shirt is also not flattering if you have thin arms because the contrast highlights your thin and skinny arms. At the same time, if you have a little bit of a belly, maybe some love handles maybe man boobs, a t-shirt will always accentuate all those flaws and of course, you do not want that. A t-shirt makes you always look worse than you are because it has very thin fabric and it dramatizes your bodily imperfections. If you are in great shape, if you have that desirable v- shape, if you have big guns, go ahead and wear well for the t-shirt, it will flatter your look but at the same time, it is not proper for formal situations or if you go out an evening.