A frighteningly large part of my day is spent avoiding human interaction.  I take the scenic route to work to avoid traffic.  I bask in the quietness and darkness of my office in the early morning.  I don't make phone calls at work because I don't like when other people overhear what I'm saying (if they hear what I say, we're essentially interacting).  I send emails instead of making phone calls.  I eat lunch at my desk.  I walk quickly down the hall so nobody can see me from their offices.  I look down the hall before I walk to make sure nobody's there that I wouldn't really want to talk to.  I read blogs but don't leave comments.  I watch American Idol but don't vote.  I keep my head down as I walk to my mailbox so I don't have to talk to any of my neighbors, and I pretend to read the mail as I walk back to my house. 

Update (2007-03-22 1:01pm):  One more:  I go to the self-checkout line at stores.