I used to run with a friend, but she moved away and I now run alone, and it is more difficult to keep going when there is a temptation to stop and walk or have a rest. Mr Nessie has come out with me a few times on his mountain bike, and I find that I am less likely to stop if he is behind me on the bike, because I don't want to appear lazy. So now if I'm out on my own, if I feel like stopping, I imagine he is there on the bike, and I keep going.
Getting out the door is another matter. Sometimes I feel really tired when I get home from work and really can't be bothered. If it is a night I have scheduled for a run, I will put on my running kit, with a fleece on top if it's cold, and head out for a short walk. Once I am moving, I invariably break into a jog/run which often isn't as far as I'd originally planned, but sometimes is longer.