need aggression

My biggest problem is that I there are times when I need to be aggressive but seem to be incapable of generating aggression. Even guys who I have trained with have noted this. How can I become more aggressive?

Are you performing well, without another level of aggression?

Bjorn Borg & John McEnroe both has diametrically opposing personalities, both were the best tennis players of their era and fierce rivals and competitors.

Everyone has aggression when they a reason to be aggressive.

You need to discover that key, set objectives, directives, goals...

Everyone reacts/responds uniquely based on their make-up.