@Roberta,
My intention to not fix payback down thumbs (or opinion down thumbs or troll down thumbs) for two weeks, taking the first one to get myself away from the fixing habit, the second to see if not fixing made any difference, has left me annoyed and even crabbier than usual.
I don't have the temper to not thumb those back up, so I give up the experiment.
On another thread I remember saab saying she thumbed up someone three times to counteract the downthumber, but my experience is that only one of those actually works - you can check by refreshing your page, saab, if you see this.