I generally agree. It's totally stupid. The people who make trailers know how to manipulate the masses to get them to see their movies, and I've been tricked so many times in the past. Even if a movie is good, a trailer can raise people's expectations to an unreasonable level and cause them to like the movie less than they would otherwise. However, I find that if the movie is great, which is the kind of movie I like, the trailer will have no bearing on my experience.
Going into trailers with this knowledge makes them less manipulative. I can take away the flavor of the film while moderating my excitement. Sometimes, though, I'm all in, like with the Tron sequel coming soon. The trailer (in HQ here), which has been out for about a year and a half, still gets me excited, even though it's got a dubiously glossy Apple-ness to it that I'm skeptical about (although it's also called a "concept test," which may mean it's not an accurate portrayal of the real film - I hope). It better be fucking good or I'm going to start cutting myself.