What could a person do if they were invisible for a day?

Invisibility

They could steal money or clothes, etc. Visit the person they had a crush on and maybe just steal a kiss. They could pretty much go anywhere they wanted to.

Bottom line, they could do pretty much anything they want.

Another answer:

I know what I'd do, but I can't say it here! Trust me, you don't wanna know!

My Answer

And besides, stealing money or clothes is not a good idea, whether you're invisible or not. Anyway, if it's just for a day, you will eventually get caught after you're back to being not invisible and that's not something that's worth the risk. Agree?

More Thoughts

The implicit assumption in this question is thus: what would I do if I wouldn't get caught? That is, the concept of invisibility is really one where responsibility is being removed, since to see someone assigns responsibility to their actions.

This is an ethical/moral question, and boils down to decisions around one's moral and ethical makeup as it conflicts with the standards that society has set. That is, you'll likely to perform actions where your own moral standards differ from that of society, such that society's standards prevent you from following your own moral/ethical ideals.