Speed does not seem to come naturally for me. I'm not genetically predisposed for lightning fast paces. Although at one time, I could not even run half a mile without feeling my lungs or heart or possibly both would explode, and here I am now doing long runs in the teen miles. I know I haven't fully explored what my body can do in terms of speed. How fast am I capable of going, with proper training? I highly doubt it is a pace that would break any records (or even win the local 5k), but I hope to find out.
My first 10k, a 1:02:55 effort. A year later, I ran the same race and beat my time by 7 minutes. Hooray!
I definitely am a fan of PR's (personal records) as a measure of improvement. Even if I am not on the fast end of the running spectrum, there's always a previous race time to beat. And if no old people or children pass me during a race, well, then, that's just icing on the cake!