Funny you ask. I love running by myself, except when I try to leave, Dirk (my dog) FREAKS because he really wants to go too. So, I usually take him for a mile to a mile and a half, or until he poops out, then I finish the rest of the run by myself.
I really don't like taking him because he doesn't run that well and I'm always afraid he's going to dart in front of me and make me fall....but it's sooooo sad to see him get all excited then me not take him =)