Form matters when going heavy, bad form can be a result of two things: ego lifting, inexperienced, or worse, both. Many bros that come to the gym are lifting to show off how much weight that they can lift and usually it is with terrible form.
Worst Squat #1
The guy in this video is probably the king of ego lifting when he attempts squatting 880 lbs with probably the worst form ever caught on camera.
Worst Squat #2
Why do people put so much weight on? Just keep the form right!!