One thing is that I totally fall apart when I'm not on a treadmill. TOTALLY FALL APART. The unsmooth surface, the lacking of numbers in front of my face, the reliance on ME to control the pace, etc. I LIKE the treadmill - it's probably related to my controlling personality.
This is one reason why I am glad that I don't have access to a TM. It has forced me to get outside and do what I need to do. I use the CardioTrainer app on my phone and it does keep your pace, but mine seems a little wonky and lags, so I'm still not 100% sure that the pace I'm going is where I should be. It's forced me to be more in tune with my own sense of pacing. No TM has also forced my rear out the door in the freezing cold (okay, freezing to me in GA, although it DID snow last winter!

) and it makes me feel good about my discipline - that is linked to my pride, as last year was my first exp. with running and racing and I was NOT about to make an a** out of myself by not training b/c I was lazy.
But those that are sole TM runners shouldn't be too freaked out by the princess - remember, there's all sorts of stops for pictures, so your pacing might be a bit "off" anyway. Also, it's just SO flat (except for those **** on-ramps!) and you are running on road, not busted up paved or gravel trails. Also? It's just so fun that you really forget to be all uptight about stuff!!!