The best thing about being an engineer is that you're being paid to think. There are so many jobs and even "careers" that simply have you going through motions. Personally, I've been building a skill set since day one and it gets utilized more and more every day. When you have a unique blend of skills and knowledge, you become the "go-to" guy or subject matter expert within a company. It's very gratifying to feel that what you know is valued and used in directing things like product development.