Design Patterns

/prog/,

I'm now reading ``Head First Design Patterns."^[1]
When I'm finished, can I expect to be an EXPERT SOFTWARE DESIGNER???

Notes                                 
1. http://books.google.com/books?id=LjJcCnNf92kC

I never read any book about design patterns because I knew people who did and they would never shut up about them. Those people were so fucking annoying that I didn't want even risk turning into them. I get why design patterns are useful (a pre-assembled way of making up for the lack of some feature in your language), but I don't get what all the hype is about.

Why the fuck some people become so fanatic about design patterns that they end up overdesigning every shitty piece of code they have to turn out? Also, is UML really useful?