Overthinking

I read an article by a runner once that seemed to suggest during a long race to chronicle your 'feelings' at set times throughout the race to track your progress and use that for training purposes later. It seemed like a decent idea, so I was thinking about that and thought what if you took it further, and made it almost a facebook-like treatment of your training related feelings. What if every hour, every day for months say you wrote down your feelings about running, even if its just one word.

Would you be able to learn something useful about how you're feeling during your training? Or would you instead be participating in a self biased experiment and would just become how you think you want to feel? Or even worse would you just end up overthinking everything?