The difference between an amateur and a professional is in their habits. An amateur has amateur habits. A professional has professional habits. We can never free ourselves from habit. But we can replace bad habits with good ones.

Turning pro is a mindset. If we are struggling with fear, self-sabotage, procrastination, self-doubt, etc., the problem is, we're thinking like amateurs. Amateurs don't show up. Amateurs crap out. Amateurs let adversity defeat them. The pro thinks differently. He shows up, he does his work, he keeps on truckin', no matter what.

Steven Pressfield Quotes