adrianna:

And PS: There is NO instance where a bra is necessary. Maybe you don't want your co-workers fixating on your chest, but that's up to you.

I really must disagree. I actually find going without a bra extremely uncomfortable. Maybe it is because I come from a long line of busty women but I have had occasions where I would prefer to sleep in my bra for the additional support.

I am not that big, just a D, but especially around the time of my period I need to wear a regular bra and a sports bra to hold me down to excercise. I can't run without very firm support.