I have been cycling for 4 and half years and i found that I have steadily improved my speed, but it has sort of plateaued. I haven't been working on speed as much and I really don't care. When I ride alone, I work on it or when I am with my husband, but he is not so much about the speed anymore and is perfectly happy to ride at a 15 mph average. I know I can never beat him on the hills (there is no such thing as flat riding here). I am now leading rides and most of the other people I ride with average a couple of miles ph less than me. It's fine. I get to stop and take a drink or just slow down and talk. I find that I feel better when i go slower on some days, mixed in with faster days. This strategy pays off when you are riding 40+ miles. I am never going to race, but I do notice I get a little competitive with certain other riders. I also like to be outdooors and enjoy, so there's nothing wrong with that. Going slow is better than not going!