But how do you even get it wrong? A separate tab opens when you click "merit" and you get to enter how many merits you want to send to that post.
Mistakes come with volume 
Up to last Friday, I've sent Merit 7381 times. I usually open the Merit link in the background, then go through a bunch of them at once. I remember once Meriting the wrong post (which wasn't so bad anyway) because of using too many tabs at once. And there's this post for post, better or worse, but that user is stacked on this 40 merits that you gave him/her and left the forum, since that was the last post from that user
on the one side one can think that you provided him with good value, with this 40 merits, but obviously that did not work, since there is nothing more from the user after that, may be a "40 merit curse"
