2. Sacrifice form just to increase weight.
For two reasons. First, poor form will inevitably lead to injury on a long enough timeline, which means you won’t be lifting at all and your muscles won’t be receiving any stimulus. Second, poor form is a shortcut, often curtailing your range of motion and limiting the amount of work your muscles are doing. If it’s easier, you’re not actually exposing your muscles to the work they need — and you think you’re giving — to get stronger. You’ll still gain muscle with bad form, but it won’t be as effective as the weight would indicate and you’ll eventually hurt yourself.
A perfect example of this is the perceived dichotomy between the front squat and the back squat. Although back squats allow you to lift more weight, they’re often harder to do right, and a recent study suggests that doing the front squat, which many find to be a more intuitive lift, with a lower weight can be just as anabolic as doing a back squat with a higher weight.