@wayrus just click the "solved" icon rather than thanking...
Well, there's nothing wrong with saying thanks... but yes, getting people to mark their own threads as solved is what we are trying to do.
So both things are preferable!
e.g. supposing someone marked a post as the solution after someone answered it, I'd be relieved - but I'd also think they are a bit of a wanker if they didn't say thanks as well... whether it be in the form of a message or a like.