Easy to say when you have small breasts. I have 10G breasts. They're really big, even though I'm slender. I sometimes go braless, but feeling the skin of my breast touching my ribcage isn't my favourite sensation. I like wearing a bra for that reason. Also if you have big breasts and you do anything more strenuous than walk, it is NOT comfortable to have heavy things bouncing and pulling at your chest with every step.