Lots of people believe that they have some sort of advantage in playing single-hand blackjack. In reality, you'd have to be an advanced player and expert card-counter to get any true advantage. Even then, it would probably be minimal.
Regardless, casinos tout the single-deck blackjack as being better for players, luring them into thinking they have some sort of better odds at winning, when in reality all they are doing is luring gamblers into a game that pays off less if you hit it big.
In standard blackjack, using multiple decks as they do at most tables, the payoff for a blackjack is 3:2, meaning if you bet $5 you'll win an additional $7.50 (1½ times your bet).
However to supposedly counter the "advantage" the casino is giving you in single-hand blackjack, they often reduce the payoff on a blackjack, meaning that if you bet $5 you'll win an additional $6, instead of the $7.50 at a regular table.
Since the average Joe will not gain any advantage playing a single-deck blackjack game, all you are really doing is giving up $1.50 every time you hit a blackjack on a $5 bet.
Before you sit down at a blackjack table, be sure to check the payout odds, which should be posted either on the felt of the table or on a sign. If it pays 6:5, move on!