With full acknowledgement to Merriam-Webster:
Definition of NEMESIS (nem·e·sis)
(1) the Greek goddess of retributive justice;
(2) one that inflicts retribution or vengeance or a formidable and usually victorious rival or opponent.
We all have at least one, or more likely, several in all of the varying facets of our being. Perhaps it's more than just a single person in a standard setting. Maybe a group of people, maybe a situation, maybe a company or authority figure. A nemesis can take many forms and shapes if we step back and contemplate.
Now that I've tried to establish this post as an insightful and philosophical piece of electronic literature, if you are truly a cycling dork, you probably have a few you can rattle off based on your last ride or race. Think Jan Ullrich and his TdF nemesis if you want to take it to a cycling macro-scale.
I myself have my share of cycling related nemeses (that's the plural of nemesis for you folks up there in the Oswego County area). Some are quite easy to identify.... you look at the last 5 races you have done and there is that same freakin guy beating you over and over. Or better yet, crossresults.com or similar even "calculates" it for you in case you can't tell. These are your apparent nemeses. Although you receive a regular ass-kickin, you know what to expect most of the time and can handle it for the most part. The truly dangerous nemeses are the "subtle" ones. These are like the passive-aggressive types of the nemesis world. They lie in waiting looking all cool and calm and then try to put a smack down on you with an aggressive attack.
Such is my nemesis .. the Branta Canadensis with it's subtle and serene yet surprising aggressiveness. These bastards can be spotted in all sorts of locations (but mainly near water). They are especially plenttiful along the Old Erie Canal towpath where I like to ride frequently. These damn animals, all decked out in their sleek yet mysterious black and white, put me on edge in that they put out little "land mines" that I have to either dodge or pay the consequences. (Look me in the eye and tell me honestly ... do you know what it is like hoping above all hopes that that was mud that just flipped up off your tire into your mouth?) Then, should I happen upon a family, the get all hissy and puffy and have even tried to jump me as I ride by. I have been tempted to break their scrawny little necks when the come at me but I have shown restraint in starting a physical altercation. I will admit to cursing a few out on occasion imploring them to waddle their cocky azzes out of the way so I can get by. So now that I think about it, they are Canadian and all the Canadians (or Canadiens) I have ever met are pretty cool folk so I'm not sure what the story is or why they always act so pissy.
So go forward with an eye on your nemesis, keep your mouth closed, and practice your handling skills cause I am sure my nemesis is more than willing to be your nemesis.