Had a bit of a crap morning after an argument with my partner but I thought I'd take it out on the treadmill. No more practice running this time, the mantra repeating really worked! Got really tough about 12 minutes in, so I kept saying (quietly, so not to attract the attention of the other treadmill hamsters next to me) 'This is what I came for/This is what I came for' just as you suggested and it worked a treat. (The smiling not so much as I couldn't do it with out looking like a psychopath...)
I've also noticed how quickly my heart rate comes down during my cool down. I checked on it mid run just to convince myself I wasn't actually dying and that I could indeed keep going, no excuses, and it was about 170. One minute into my cool down, it was back down to 130, and with a bit of deep lovely breaths, even lower. Hope this sounds about right? (my heart rate has always been very high, and my blood pressure very low, much to the confusion of each GP I'm seeing for the first time).
Anyway the_tea_fairy you were a lifesaver this run, as have many others on here with their oodles of advice been on other runs for me and us all.
Just one more to go for me before graduation