When we listen to all the forums and websites out there, a common theme is the issue of variation. It can be described as a run of good luck, or more often a run of bad luck. Although there are definitely patterns and cycles of good and bad cards in any deal, my latest hypothesis is that it is partly caused by the way we think.
Our perception of our recent "luck" is based on the way we remember things. We tend to remember the losses and the "bad beats" much more than we remember the suckouts and good plays which benefited us. Part of this has to do with our ability to adapt. You can see this every day in your life outside of poker (you do have a life outside of poker, right?) We quickly adapt to a noisy or smelly environment and soon don't even notice, until you leave and come back, or someone else points it out.
The same thing happens at the poker table. When you start to play at new table, it takes a certain amount (results vary by player) of time to get familiar and adapt to the play at the table. If you play tournaments, like I do, you may end up changing tables a lot. To make this worse, if you play at multiple sites, the play at each site can vary hugely. Once you adapt, your perception adjusts to this new baseline and your memory of how you played highlights a completely different level of play.
All in all, this means that when you think back over the last month, your recollection of your play focuses on the exceptions to your changing baseline. Your mind convieniently flattens the baseline and gives you a distorted view of your play. In some cases, this make you think you had a consistently good (or bad) month, when in reality your play was probably varied than you think.
Before you say, what about the reports I get from tools (like pokertracker, or whatever), I want to make a comment or two on them. I actually like them, but they are potentially part of the problem if they are not used correctly. The problem is they go exactly the opposite direction and try to assume a completely unbiased rating. Good play is not the same from one table to the next, never mind one site to another. The same can be said of bad play. Although they can give you stats like VPIP and showdown % and any other stat you can think of, these measures have the most value when measured against the table average in each case.
Are they useful? Of course! But like anything, they are just one form of feedback and you have to figure out how to incorporate them into your mental picture of how you are doing.
Perhaps this is obvious to everyone but I figured I would try to articulate it and see whether this makes sense in writing. Your feedback and/or comments are always welcome.