Check out the book - 'The Non-Runner's Marathon Trainer' - really inspirational and has some great lessons for training and for life as well. In chapter 2, it talks about focussing on the positive with the phrase '...but it doesn't matter'. So if you catch yourself saying 'I am tired' or 'it is raining', or 'my legs are sore' or 'I need someone to run with' - simply add the phrase '...but it doesn't matter!'. Just get out there and do it and run - you'll be glad that you did when you are finished. This attitude has everything to do with life, not just running. With this point of view, we can overcome obstacles to running, exercising and whatever obstacles we face in life.