The K-22 I purchased recently had the rear sight cranked all the way up and to the right. No doubt the previous owner thought it shot low and left. If you go and look at the rear sights of just about any used handgun that has adjustable irons, you'll probably notice the same. It's an epidemic!
One time I had a guy come off the range at CCA with a target in his hand and an upset look on his face. "The sights on this gun are off..." he began.
"You're left-handed, aren't you?" I interrupted.
He looked as though I'd just pulled a quarter out of his ear. "Yeah. How did you know?"
"Because you're hitting low and right instead of low and left."
Xavier has more on the problem, as well as a pointer to some advice on solutions.
One of the best instructors I'd seen when it came to actually teaching new shooters to hit would stance behind them and murmur "Okay, take your time. You're not trying to make the gun go off. You have all day. You're just increasing pressure on the trigger gradually, that's all. You're not trying to make the gun go off. Just slooowly increasing the pressur..." and BANG! Nine times out of ten, the result was a perfect bullseye. Most novice trigger control problems are caused by trying to make the gun go off rather than just pulling the trigger and letting the break surprise you.