On a repeater, talk like you are face to face with someone you don't know or are on the telephone. When you turn it back over to the other op, say back to you(name or callsign) this is (your call). I hear a lot of people using their callsign and then saying for ID. There isn't any need to ask for a signal report(at least on my local repeaters), if you are barely making it into the repeater or have some noise, they will tell you- and not trying to be mean about it. Saying roger, roger instead of I understand bugs me as well as Hi, Hi instead of saying "that's funny" or "that's a good one". Hi, Hi is used on CW to replace a laugh, in CW it actually sounds like a chuckle of sorts.
But I am not one to bash someone on the air for it. It depends on how the club is that owns the repeater whether they are a strict bunch or some guys that got licenses to have fun on the radio, the W6NUT repeater has gotten a bad reputation for what is discussed but as long as the FCC rules are followed, nothing will happen.
And then there is a repeater in Canada where it seems that the club members are just trying to get the other amateurs upset. Somebody even posted a bunch of audio on youtube and it can be amuzing when you figure out what's really going on.
You're not going to like everyone you meet on a repeater, like real life. It's ok to laugh on a repeater, if someone doesn't like it, tell them to pound brass