You're running into the same problem many of us have -- if you're sitting at a desk that has a phone and a computer up and running and connected to the internet, the various contexts are all equally easy to reach for.
There was a thread awhile back that Siva started about this -- people customize their contexts depending on personal factors sometimes. I.e., if you have x hours of quiet in the morning before the kids come home from school, then @quiettime might be a context for you. Also, if you have times of day you are doing the laundry, handling the kids, etc., in between your work, you might classify those actions as @interruptable or something like that. Or, if the people you must call are on the east coast, and you're in California, you might have a context for @MorningCalls.
Personally, I don't break things down at all. I have @Work, @Today and @Waiting For. I have been trying to use @Calls, but to tell the truth, I never look at it. Things tend to stagnate there.
You could have a category for @HighMentalEnergy and @FillingStaplerTypeStuff, or whatever you think works for you. You just have to think about what sorts of contexts drive your day.
HTH
Taxgeek