It's a Journey
Here's another typically excellent article by Jack Slack about boxing in MMA. The whole article is worth reading, as are all of his writings, but there's a line about halfway through that I thought was worth spending time on: "Good boxing is something you perform throughout the fight, not something you go in having." Whether or not you have excellent boxing is not necessarily an important question for self-defense, but you can substitute almost any quality for the word 'boxing' in that quote and it still applies. Aggression, intensity, toughness...these are not personal attributes that you either have or don't, they are skills that you constantly work to implement and develop. Like the earlier post about getting techniques "right," the issue is not "I'm not aggressive," it's "How am I using and improving my aggression right now?" So shift your focus from, "Am I good at X?" to "Am I using X well?" You will find your training much more satisfying.