In fact, the hell with being a scientist, people typically can't plan their life period. People may have a general idea "oh i want to work in the science field" or "I don't want to have too many kids", but when you try to sort out the details, things typically will fall apart on you within months. You may decide upon a plan, but the world doesn't care what your plan is.
On a personal note, I have an example that fits this idea well. I was hoping to go to a phd school in California in a physics department. I put extra attention into my application to UC campuses. I figured I'd go to a school, get a TA position, not have to pay for anything. What ended up happening? One of the departments I applied to didn't even allow admissions this semester (possibly shutting down?), the UCs get huge budget cuts (I heard some departments cut enrollment by 2/3), and I got rejected by most of them. Now I'm going to end up at Georgia Tech in an engineering department (although the work is the same so it's not really a big deal).
The more I look into the real details of living in Atlanta, it ends up looking like I almost missed the greatest opportunity ever! Without going into the details, it looks like a fantastic place, a great school, and my quality of living will probably be a whole lot better compared to living in a cramp space with 3 other people barely getting by in a desert climate in a state that's falling apart (I won't exactly name which UC I'm talking about). The point is, don't try to plan out your entire life because you might find that you're going to get knocked off that path and onto an even better path in the end.
