Think about this every day:
The question isn’t who is going to let me; it’s who is going to stop me. ~ Ayn Rand
If you aren’t comfortable with this attitude, it’s hard to be awesome. Sorry. You can be good enough without being assertive, but to a large extent, being awesome requires that you initiate, take action, and chart your own course through the norms of mediocrity.
I'm overdosing on Ayn Rand quotes (two per week is a bit much) but this is a great blog post by Chris Guillebeau.