Ask HN: Why are many people so bad at opsec?

Because I swear, we hear about a new 'anonymous source' or darknet market owner getting identified every week or so now, and it just makes me wonder why. Why, despite all the want for anonymity online are people so bad at keeping it going? What makes so many people trip up, even the ones whose lives and occupations rely on staying out of the public eye? It's not like it's theoretically impossible; Satoshi Nakamoto figured it out pretty well when creating bitcoin. And surprisingly, quite a few people seem to do pretty well without trying. Like various fan game and game mod creators, some of which seem so secretive that you wonder whether they're still alive or not. So why does everyone keep tripping up here?