But I tell myself: "This is not what I want to do with my life. I'm doing this as a favor to my aunt. I'm doing this on the side, just to make enough money to keep working on the stuff I really want to work on. That is my real focus, designing web-pages is not." And then when people say, "That's great!", I tell them the same stuff I told myself. I think saying the words out loud to others helps me convince myself on a deeper level.
So maybe by affirming your own values you can allow what you really want to be focused on to naturally rise above the petty stuff.
I also agree with disputes being a huge distraction. One guy I used to work with is extremely contrary by nature. He would argue with anything I said, seemingly out of habit more than anything else. After arguing with him, I would invariably find myself turning over the argument in my head and having a hard time focusing on work. Eventually I decided the guy was hurting me more than helping and that I needed to stop working with him. There were several other factors involved, but that was a big one.
One way to avoid disputes like that is to be single founder. Or at least seek out a co-founder who is agreeable. I watched an interview with Larry and Sergei the other day. They were asked, "What do you guys argue about?" and they seemed kind of stumped for a moment before one of them said, "We don't really disagree about much..."
This essay also helps explain the vague sense of frusteration and despair I feel whenever a friend wants to visit, or whenever I need to visit my family. Inevitably interpersonal relationships end up forcing their way to the top of my brain. Living a monk-like life of isolation is the best way I know of to focus on real problems.
Lastly, I think it is possible to do "ambient thinking" intentionally. Just sit or lie down somewhere comfortable (but not so comfortable you fall asleep), and do nothing for several minutes. Time passes amazingly slowly when you're doing nothing, so you don't need to worry about wasting time. Your mind will naturally start defragmenting itself and playing with various ideas -- at least mine does.