Piece of Basic Strategy people are most reluctant to follow

For some reason of all the parts of Blackjack Basic Strategy the thing that it seems that players are most reluctant to do is split a pair of 8s against a high dealer upcard (i.e. 9, 10, A). Often they say that they don't want to turn one losing hand into two losing ones, but the math shows that splitting results in an average lower loss than playing the hand unsplit. Does anyone know why people often think this way? Any other parts of BS you have heard people "contest"?

Splitting 8s against a 10 or A is a borderline play. You have almost the same chance of winning as with hitting or standing. Splitting them against a 9 is a must-do. You have to hope you will get two eighteens, and the dealer will have seventeen, eighteen, or bust. It's hard to see the advantages right away, but thinking of it like that makes it easier.
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The other B.S. play I have seen most ignored is hitting a soft eighteen against a nineteen or twenty. This is another play where it's hard to see the advantage on it's face. Some people also don't like to double eleven against a ten. I can't really blame them for that, since they are lessening their variance without giving up too much of the house edge.

In terms of lost expected value, I think the greatest mistakes are made not doubling soft doubles against weak dealer cards. Seldom do you see recreational players do that. If the player never invokes correct soft doubles it increases the house edge by 0.09%.

If the question is what play are recreational players most likely to not make correctly, I would say 44 vs. 5 or 6, when double after a split is allowed. Even dealers often roll their eyes when I split them, and other players shake their heads, as if to say "what an idiot."

I doubled a soft nineteen against a six at the Venetian and the dealer looked at me with abject pity like I was a mental retard or something. She was an otherwise sharp and friendly dealer, so I wasn't going to challenge her on it (it was the right play in a double-deck H17 game, and I won the hand).

I doubled on a soft twenty against a dealer's 5 and was vilified by the dealer and anothor player. I thought it was the right play. It was a double deck game with the count +5. I lost the hand but the dealer and the player at the table thought I was nuts. Was I?

Quote: luckyjackg

I doubled on a soft twenty against a dealer's 5 and was vilified by the dealer and anothor player. I thought it was the right play. It was a double deck game with the count +5. I lost the hand but the dealer and the player at the table thought I was nuts. Was I?

Probably. I'm not sure of the index number for that play but it is not a basic strategy play. That is similar to splitting tens.

Probably hitting 12 against dealer 3. I've even had dealers tell me not to do it.

Quote: Kellynbnf

For some reason of all the parts of Blackjack Basic Strategy the thing that it seems that players are most reluctant to do is split a pair of 8s against a high dealer upcard (i.e. 9, 10, A). Often they say that they don't want to turn one losing hand into two losing ones, but the math shows that splitting results in an average lower loss than playing the hand unsplit. Does anyone know why people often think this way? Any other parts of BS you have heard people "contest"?

As you correctly pointed out, any time you start with one hand with a negative expectation and BS requires you to put out twice as much money (either by doubling or splitting) just to end up risking twice the money with a negative expectation. You have to trust the mathematics of all the possible outcomes rather than how it feels to you. But even the mathematics does not show a great improvement with the BS play.

It is easy for people to understand splitting 8's against a dealer 7. You start with a single hand with negative expectation, and end up with two hands both with positive expectation. I refer to this case as the greatest possible improvement in blackjack play, because the correct play (splitting) has the greatest increase in EV over the other three choices (stand, hit, double). It's a subjective name, because I am ruling out bonehead plays like hitting 20's.

Novice players want plays that feel like the greatest possible improvement play. Of course, if every choice was that way you wouldn't need BS. The reason you memorize BS, is how to choose the better play where both possible choices are giving you a negative expectation, and you want the least worst choice.

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I didn't see the movie 21, but there was a line where the MIT professor says that splitting 8's against a dealer 10 was a sucker bet. It may have been a set up line in the movie, because presumably if you are writing the script for a movie about blackjack, you would go to a store and spend $3 on a cheat card.

Quote: Wizard

In terms of lost expected value, I think the greatest mistakes are made not doubling soft doubles against weak dealer cards. Seldom do you see recreational players do that. If the player never invokes correct soft doubles it increases the house edge by 0.09%.

If the question is what play are recreational players most likely to not make correctly, I would say 44 vs. 5 or 6, when double after a split is allowed. Even dealers often roll their eyes when I split them, and other players shake their heads, as if to say "what an idiot."

44 against 5 or 6 is a tough one especially at 3rd base. You draw a couple of 10s to stand on two 14s and you'll have the table shaking their fist at you when the dealer pulls an ten and then draws a 5 to make 20 or 21. You just gotta do the math though and stick to your game plan. I remind people when a questionable (yet correct) play has a happy ending, and jostle them back just as much as they mess with me.

As I wrote in another thread, the chart I use came from a book that lumped all "Las Vegas Multiple Deck" games together. As such, I don't have all the slight variations for 2-deck, DAS, or even H17 vs. S17 (the book acknowldeges that at the time, Downtown was generally H17 and the Strip was S17... but it doesn't have separate charts).

Comparing to the Wizard's 2-deck H17 chart, I would not be making the following plays:
double 9 vs. 2
double 11 vs. A
double A3 vs. 4
double A7 vs. 2
double A8 vs. 6
split 44 vs. 5 (if DAS)
split 44 vs. 6 (if DAS)
split 66 vs. 7 (if DAS)
split 77 vs. 8 (if DAS)

I've gotta assume that these are very very marginal plays. But if I'm gonna use a chart, I may as well use the right one. What is the edge on the above plays?