What's the best thing to do if you think you see evidence of trolling?

Probably, we all have different standards for trolling. I’ve seen people claim that there is trolling here, but I don’t know what they are looking at. This annoys me. Is it trolling to claim trolling when there is no trolling (or even if there is trolling)?

I think it only encourages trolls when you point out trolling (assuming they are real, not accidental trolls). I think the best response is to ignore the troll, and let others do as they will with respect to the troll. I think the moderators here do a fine job of removing inflammatory posts. If I see something that annoys me enough, I can complain to a moderator. That’s good enough, I think.

What do you think is the best response if you think trolling is going on?