The difference between dog shit, and Halo 3 and Halo Reach, is that they're considerably more enjoyable. Rather than dog shit, where there isn't a good number of people who enjoy it. There is a very good number of people who enjoy the game, a lot. It isn't a very good analogy. It's not the same logic. There are aspects of Halo Reach and Halo 3 that I like more than Halo 2 and Halo CE, and there are also aspects from Halo CE and Halo 2 that I like more than Halo Reach and Halo 3. Some of these aspects weigh out others, determining mine, or other peoples opinion.
Also, I'm sure that there are people out there who do enjoy eating dog shit more than filet mignon, some people do crazy stuff.