The ability to regulate your emotions is one of the most important life skills you can possess. Why? Because lack of emotional control can wipe out any other skills you might have.
Former FBI head negotiator Chris Voss addresses this issue in his book Never Split the Difference:
"There's one vitally important thing you have to remember when you enter a negotiation... without self-control and emotional regulation, it doesn't work. The very first thing I talk about when I'm training new negotiators is the critical importance of self-control. If you can't control your own emotions, how can you expect to influence the emotions of another party?"
A negotiator can have a solid strategy in place and know all the best techniques, but if they lose their cool in the moment, they can destroy their entire plan and blow up the negotiation.
I think of strong emotions like blackouts that temporarily disable the entire system. While emotions cannot be ignored completely or indefinitely, a good regulator can postpone the blackout to a non-peak time. When the stakes are lower, emotions can be acknowledged and processed more calmly and safely.
The Incredible Hulk really is a great example of how temporary moments of insanity can wreak lasting damage. What he does when he's in a rage takes longer to repair than it did to set in motion. It's easy to say or do idiotic things when under the influence of a powerful emotion, and it's hard to undo the consequences.
If you build up skills, but neglect to develop emotional control, you leave your ability to use those skills at the mercy of anyone who upsets you. You put your power in someone else's hands. Learn emotional regulation, and keep the power in yours.