Dealing with an imperfect GTD system

A perfect GTD system only exists on paper. Of course everyone's system is imperfect. We should be able to deal with that. I like to measure imperfection as how much stuff is still on your mind. That's what drew me in and keeps me going strong with GTD: keeping my mind clear. In the end, this is simply what eliminating stress is isn't? Getting rid of the constant nagging, worrying thoughts that make life miserable. They suck, and I want them gone.

So a question I've been asking myself is what happens when a project or two, or a task or two starts to consistently bother you? (Mind you this can happen even with a perfect system. GTD does nothing for emotional reactions towards certain tasks or projects. In fact, what system would make a project like "Defend thesis" get off your mind as the defense deadline approaches?)

Being anxious about your defense is normal and even healthy stress, but sometimes tasks or projects that I don't need to be thinking of all the time bother me. Usually this is because of some hole in my implementation of the system: I didn't do enough front end planning, the next actions are too big to handle, or something of that sort.

I've found the best way to deal with this is simply to do one small task related to that project as soon as possible. It's a huge stress relief. The more you procrastinate on something the more intimidating it seems, so breaking that chain and just doing something, anything, does wonders for making the project and the other next actions seem a lot more digestible.