I feel like there's a bias for this, where you likely wouldn't register seeing a mundane number a bunch (like say, 378), but 666 and 420 would stick out even once, so you'll remember all the other times you've seen them. From googling though, I'm having trouble finding a name for this that I'm familiar with; the best I can find seems to be salience bias[1], but I'm not sure if that's what I was thinking of; I've certainly never heard of it before.