“You should sit in meditation for twenty minutes everyday - unless you're too busy; then you should sit for an hour.” - Old zen saying
This quote exemplifies that when the mind is anxious to play, it probably means that you need to calm down first more than ever, and then play.
It's good that you feel eager to play, it's way better than feeling without motivation. What's not good is that you want to play at the expense of your performance.
The professional is patient and does what he knows he should to to get ready and perform at his best level no matter what happens.
The Warmup is not a waste of time, is an investment of time that increases your performance and makes the time you spend playing more efficient and valuable.