When a player holds a 9-3 (12) against a dealer 3 upcard, he is reluctant to hit for fear of drawing a 10 and busting, especially when the dealer is showing a “weak” upcard.
Players understand why they shouldn’t hit a 16 when the dealer shows a 6 upcard or why they should split 8s against a dealer’s 5 upcards.
When a player is dealt a 6-5 against a dealer’s 10 upcards, more often than not he will hesitate doubling down.
Most players stand with an A-7 (soft 18) against a dealer’s 9 upcard, reasoning that an 18 is good enough to beat the dealer.
If you stand, you’ll win about eight times out of twenty. If you hit all the way to soft 19, a hard 17, or bust, you’ll win nine out of twenty.