I was a lot like you in school. Figured in high school that I really wanted to be a software entrepreneur, went to college mostly to satisfy family obligations, majored in physics because I thought maybe I could be a famous physicist in my 4 years (hah), hated it. I flunked two courses in my major, nearly dropped out both times, and of course was on academic probation for a good portion of the time. The last time was with one semester left, and was rather tricky because I suddenly needed two physics courses to graduate and they were never offered in the same semester.

I did end up finishing, with a CS degree. It was much like the guy with the Ph.D said: I figured that if I had a business, there would definitely be times when I had to do things that were boring and not directly applicable to what I really wanted to be doing. If I looked at that last semester as practice for my business, it wasn't pointless anymore.

One other observation: if you want to succeed in business, you need a healthy respect for randomness. I remember, when I graduated, I had this big plan for my life. I was going to work for someone else's startup for a couple years to learn the ropes. Then I'd quit and start my own. We'd build something cool that lots of people wanted, then get bought out by Google where I'd have tons of fun playing with their massive data stores.

Life doesn't follow plans.

Or rather - you can follow plans, but there's no guarantee that life will follow along. I did end up working for someone else's startup for two years. Then I started my own company, right on schedule. But we got stuck on the "build something cool that lots of people want". And of course that blocked off the "Get bought by Google" part.

So when I had the chance to join Google as an employee, much less wealthy and less accomplished than I'd hoped, I took it. Because I realized that adding that extra "by Google" clause to "get bought" drastically reduced the chances of getting bought, and adding the "get bought" clause drastically reduced my chances of building something cool that lots of people want. In general, the fewer conditions you attach to your goals, the more likely they are to come true.

I think a lot of people make the mistake of cutting off potentially promising avenues far too early. Real life success is never this linear path where everything works out. It's more like a pinball game where you bounce around from bumper to bumper, sometimes falling back but hopefully moving forwards (and you need a lot of balls to win!) Things like getting a degree or investigating big companies to work for may seem terribly boring, but they can open up doors that may be really interesting once you look through them. It's better to look first and then shut the door.