Walk onto the weight room floor and you’re likely to see guys using form or doing exercises that will make you cringe. But these obvious errors are just two of many possible ways you can screw yourself in the gym. With so many pieces of equipment to choose from, it’s hard to set up a proper routine—let alone get the warm-up and all of the other components right. Although some of these mishaps may be minor, they can actually lead to huge setbacks in terms of gains. To save yourself time, get f...