I've been doing a bit of badge hunting recently.
I was under the impression that badges were supposed to incentivize positive behaviour. The tag wiki for badges even says so.
Badges are awarded to encourage and incentivize positive community actions within the site.
Most do just this (e.g. Great Answer, Booster, Teacher etc.). Some badges are just incidentally rewarded after doing something trivial (e.g. Critic). These types of badges are fine.
But then there are some badges that reward unconstructive behavior. Here's a few that I have, with an explanation of how I got them:
Asked a question with no votes, no answers, no comments, and low views for a week
This one was pretty easy. All I had to do was post a nonsense question that people are likely to ignore. (at the time the badge was rewarded, it had 0 votes, answers, comments, and 21 views.) This badge encouraged me to post pure noise.
Deleted own post with score of -3 or lower
This one was incredibly easy, as well as perversely fun. All I needed to do was answer a C++ question with something along the lines of
C++ is an ugly language with all sorts of platform dependent behavior. Just drop whatever you're doing and use jQuery instead.This took a matter of seconds to accumulate three downvotes, after which I deleted the answer and got the Peer Pressure badge. I self-instigated a rep recalc and promptly recovered the reputation lost from the deleted post. If this isn't a badge that promotes bad behavior, I don't know what is. This made me realize that I can freely post as much pointless and stupid content that I want with no penalty as long as I delete it later.
Deleted own post with score of 3 or higher
This was pretty easy, too. I just deleted an old answer that had 3 upvotes. This badge encouraged me to remove potentially helpful content from the site.
There are a few more badges that seem to encourage less-than-helpful behavior (Vox Populi, Strunk & White, Taxonomist) but I don't really feel qualified to elaborate on why because I haven't obtained them nefariously (yet).
I'm not suggesting that these badges should be removed, becase, frankly, I'd like to keep them. Whenever you introduce new badges, though, I think it would be prudent to carefully consider whether or not they are constructive.