[AstralStorm]

Casually a trained badass (or a sufficiently unhinged person) will ignore that punch and proceed to destroy you. So unless you're a super trained boxer and can knock out everyone in one, it's a waste of time.

You lost the element of surprise and tempo. If you want to do some damage, do it, not rely on the opponent obliging or complying.

[varjag]

Everyone Has a Plan Until They Get Punched in the Mouth - Mike Tyson

[RealityVoid]

Certainly it's better to punch them than not punch them. Many many times overwhelming violence is sufficient to win a fight. Trained people might not be as phased, true.