river overbet bluff?

saw a dude pull a massive overbet bluff on the river last night, like way more than the pot, and it actually worked. dude on the other end tanked forever and finally let it go. not sure i’d have the guts to do that, but it got me thinking about the spots where people go for it. is it just a next-level confidence thing or is there a real strategy behind when to size it up so big?

i deal mostly low stakes so i don't see this all the time, but every now and then someone pulls a huge river move and either gets called and looks like an idiot or everyone talks about how they had “the read.” curious if other folks have stories or thoughts on when this works or if it’s just lighting money on fire most of the time.