TR I didn't used to be so obsessed. I used to be just like you and run to feel but the problem was I never felt like running fast, so I would just plod on and on and on. If I tried to run any kind of interval I would think I was going to die so quickly stop. After all I didn't need it - because I could just run on and on and on. So I really need something structured to make me run 'so' fast for 'so' long otherwise I just wouldn't bother. Maybe next year I'll try Poacher's 'what if the opposite were true' approach but until then its schedules and gadgets all the way! 
You have just summed up the difference between hurting and suffering. Hurting makes suffering easier. If you look at the training schedules of people like Zatopek or Bannister, you get an inkling of how much they must have hurt themselves in order to achieve their goals. Your sub 3.15 in London will involve hurt and suffering, but it will be worth it
There once was a Bishop of Birmingham...you can complete the rest
Lorenzo - on the book front, just reading The Ghost Runner - a readable and interesting piece of social history, worth adding to the list.
5m plod today, 45m for the week and a couple of days to go