Most hobby joggers don't do what you are saying. Fast/slow or otherwise, most hobby joggers run in the gray zone all the time. We do it because we believe the no pain no gain theory. If I'm running 10 miles, I should do it around 10K pace because it will hurt and I know I worked hard for it. That's just the way it is. I hired a running coach, not because I'm going to light up the world as an almost 60 year old. I hired him so he could help me become the best runner I can be without blowing myself up. I've learned quite a bit, I'm trying new things, and enjoying running again. I'm not an ex-pro, I'm not fast enough to run a BQ, but I'm a better runner than I was before I hired the coach.