Prep courses often unknowingly add to the problem, because in their zeal to add value, they also focus on logic games, sometimes to the exclusion of the other question types- Reading Comprehension and Logical Reasoning. Once you have figured out a particular logic game, as with any puzzle, it seems easy and more significantly, can be apparently easily explained to others. The problem with this is that there really is no "pattern" to logic games (however, there is a pattern to the other question types- Reading Comprehension ("RC") and Logical Reasoning ("LR"), which I will discuss below), other than the basic question setup, which lends itself to some sort of diagram. As a result, logic games preparation generally has a lower return on study investment than the other question types.
On the other hand, RC and LR questions are almost pattern-like in their consistency. With RC questions, anyone who has taken the LSAT can recognize the pattern- a dense reading passage, followed by questions about the passage. LR questions are almost always syllogistic (meaning, "if this, then that", requiring the test-taker to logically solve the problem. As a result, both of these question types can be "drilled" through intensive preparation, and the skills required to solve these questions can be increased over time with that practice.
This is not to say that you cannot increase your skill in solving logic games problems. I'm simply saying that you can more easily get better at RC and LR questions, and more quickly, than you can with logic games. And because all LSAT questions count easily, depending upon how much prep time you have before the test, you may experience a greater "bang for the buck" with RC and LR question practice than with logic games practice.
The other thing you should keep in mind is that the LSAT is a "head game" of sorts. If you freak out during the test, for any reason, it is likely that you will not do as well as you could have. Logic games tend to freak people out, especially people who have spend a great deal of time in LSAT logic games preparation, who suddenly encounter a logic games problem that seems unsolveable. If you encounter one of those problems early in the LSAT on test day, it could potentially unnerve you to the point of affecting your overall performance.
So, logic games preparation to the exclusion of practicing the other question types is a bad strategy. A better strategy is to prepare equally for all question types, carefully monitor your progress early in your preparation, then adjust the ratio of prep time, depending upon your level of improvement. If you experience good improvement on RC, but still aren't where you need to be, for example, it may make sense to invest more time in RC prep than logic games prep.
Finally, and arguably most importantly, remember that there is no penalty for guessing on the LSAT. So, narrowing down the probable answers and then guessing between a couple of equally probable answers may statistically increase your chances of a correct guess. And a guess counts the same as if you spend ten minutes sweating through an intense logic games question.
Everyone is different. Different strategies work better for different people. But don't fall for the "logic games trap" in your LSAT preparation- spending most of your time trying to master this question type, to the exclusion of the other question types. And if you are planning on going to law school, you need to pick up a copy of my book: Law School Labyrinth- A Guide to Making the Most of Your Legal Education (Kaplan Publishing, March 31, 2009.