So heres a little request. Washing yourself! Example: you need to bath or use soap every now and then or you will begin to smell, giving you a -1 CHA penalty, keep it up for weeks and you even get -2 CHA. Or it gives penalties to Barter and Speech since CHA doesn't do a lot in Vanilla.
You could wash in clean water sources like in vaults or one of those clean basins (i.e near goodsprings), or create a menu at dirty water sources asking you if you want to drink it or add detergent and wash yourself (will give off radiation). Or just combine a bottle of dirty (will give off radiation) or clean water with detergent and use the resulting soap.

I think it would add to the realism. Theres a lot of trash, dirt and blood in the wasteland. Smelling really bad in real life would impair your social skills.

What makes me laugh is that there's actually a mod like this for Oblivion.

Except in a post-apocalyptic wasteland where everyone is dirty and smells not so pleasant. Could be just viewed as the norm now.

If you think that, then being squeaky clean could give you a bonus to your stats.

There was a mod like this for Fallout 3, too. Made you look dirty after three days, and "dirty" peoples were friendlier, while the cleanly types were even more snobby to you. Or summat like that.