@Marc Nobbs๐
Sometimes I'm the same. I agree with something, but don't reckon it warrants a written reply, but equally, I also feel that the poster needs some form of feedback (Maybe they were giving a rhetorical answer or something). So occasionally I will simply post a thumbs up. Or they might have answered a question I asked (in the forums), and I wish to acknowledge the reply without going to all the tedious and time consuming effort of typing "Thank-you".
I do agree that a simple thumbs up, or down, would be nice to have. Say someone made a post on the 'Feature Requests' forum and I thought it was a sensible suggestion, so wished to show my agreement. And vice versa, if I thought the request was a complete waste of time, then I could 'downvote' it without going to the potentially troublesome effort of typing "Go take your head for a shite..."