Perception Bias is a well-known cognitive bias, but as a neuropsychologist you probably already know thatDode74, what a negative view!
You remember your spectacular failures more than your spectacular successes?
I am really sorry for you.
Basically, people expect die rolls to pass, so when they do, it's not a big deal, just what "should" have happened. People can roll 10 2+ rolls in a row and not think of it as an extraordinarily lucky, it's what is "supposed" to happen. It doesn't mean we're stupid, it's just how our brains work unless you make a real effort to think about probability.
How many gamers do you know who claim that they have extraordinary luck? And how many do you know who claim that they're cursed?
So when die rolls fail, especially "easy" rolls like 2+ or 2+ with a reroll, it's unexpected and people notice that. In tabletop, I've seen someone make a -2d block (getting the knockdown they needed), a 4+ dodge, 3+ dodge, 3+ pass, 3+ catch ... fail the 2+ go-for-it to score ... and then throw the d6 against a wall, yelling "fuckin dice HATE ME". We've all seen it. Heck, we've all felt that way at some point. And probably nobody ever rolled a 2d block, knocked their opponent down, and took the time to say to themselves, "my dice are AWESOME today!!"
In the online version, we don't have dice to chuck, so the modern equivalent of throwing dice is to whine about the RNG. The difference is, of course, that while you can see a d6 and figure out that it's fair, the RNG is just some kind of magic that can't be tested and must be biased!
Except of course it can be tested, and has, including by people on this forum. That doesn't stop threads popping up regularly claiming that the RNG is broken, biased against certain usernames, or that the AI cheats. Incidentally, I've never once seen someone complain that their dice are too good; see above. Anyway, yes, some of us get kind of snippy and sarcastic by the 10th, or 50th, or 100th time we read that kind of thread.