Difference??

They are both grammatically correct.
The first is ordinarily a polite offer of service.
The second, less polite, at worst could be a threat, a sexual proposition, or a beleaguered parent's exasperated expression to a mischievous child. It could possibly be an attempt at humor between friends. But, I can't think of any situation where it might be considered polite.

In general, we do good things for people, and bad things to them.

Very succinct.

Yea Con, well put