I was at a Spanish 21 table where this guy would double down on a hard 12 when the dealer showed a "bust" card.
Last night, emerald casino in curaçao. Guy doubles hard 15 against a dealer jack. Pulls a 6!!!
This of course reinforces to him that he should always double down in precarious situations, and loses the next three times he does it.
For AOII, split 9's vs. an A at +9 & up for S17 game.
A guy on my table doubled down on a hard 17 when I explained to him that is a very risky move. He got the 4. I think I have told this story a few times on this board.
My girlfriend does stupid stuff like this (Teddys is a witness). Of course she gets the four and says "see? basic strategy is bullsh!t". All I can do is shake my head. A significant other who refuses to play basic strategy is grounds for a breakup/divorce.
Video blackjack machines tend to attract bad blackjack players. Standing on soft 13s, doubling on stiffs and splitting 10s every opportunity they get is pretty normal on the weekends. I was playing with a cowboy who refused to play when the Asian dealer on the screen came up. He was convinced that she was somehow cheating him.