I was out on a fine Illinois morning lifting in my garage when a young guy came by selling bug extermination services. He saw that I was lifting weights.
"So, getting a workout in?" he says.
"Yes," say I, always charming and ready to talk to strangers.
"Do you compete?"
"Yes. Powerlifting." I hope my taciturnity will get him to leave.
"Cool," he says, nodding. "I used to do a bunch of that powerlifting stuff myself."
"Is that right?"
"Yeah. What lifts do you guys do?"
At this point it's clear that he doesn't know what he's talking about. He is like many other people who think that they know all about weightlifting, because they used to go to the gym, or they've read an issue of Muscle and Fitness, or they've got a buddy who taught them how to bench press once.
I've met lots of people who dismiss my chosen avocation with an airy wave of the hand and an "I used to do that. Heck, I squatted 300 once!" Often this is followed with a "Be careful! You'll hurt your knees/back! I know a guy who blew out his knee squatting!"
Never mind that I've done quite a bit of study and logged many hours coaching the barbell lifts, or that I've been on staff for Starting Strength seminars: they've got knowledge to equal mine!
Consider whether you would do this with your doctor or lawyer. "Yeah, I know all about medicine. I once had a cut and closed it with super glue!" "Oh, I know all about the law. I read a contract once. Even signed it in the right places!"
In medicine and law you seek competence. In strength training, most people are content to rely on a few tips from their buddy. Is it any surprise that most people don't get good results?
Find a competent coach and pay what it takes to get the coaching. You can find a Starting Strength coach at Startingstrength.org.