I've seen athletes improve leaps and bounds in a matter of a few minutes. Most of the time it doesn't take much more than a simple skill change, or even a mental approach, to create large improvements.
This excites them, and makes them really love the sport. But it gives them a sour taste in their mouth when someone doesn't believe they can improve like that and therefore declare they must be cheating.
If you're blaming cheating, drugs or drafting as reasons why people are beating you, maybe it's time to re-think that strategy. Unless you have hard evidence, your perception is biased. I know people cheat, but maybe there's more to it. Don't be that athlete...