I have never been a GM before and a friend told me about GURPS which got me excited about the idea. Upon reading a bunch of the books however, I found myself making custom rules until it didn't even resemble the system anymore. I've actually poured a ton of work into every possible aspect of the game I could think of. I have yet to use it with a group but I'm not sure if this is the right thing to do. How to people approach modified rules and is this such a good idea for a first time GM?