There are a few things I try to stay as neutral about as possible. Politics is a good example. The more you get your heart attached to something, the harder it is to be objective about it, and therefore, the harder it is to make it good and make it work. But, "politics" is of course just a different word for "human nature"* so it nearly requires your heart to be involved.
Movies are the same way. I want to say that I always judge a movie on its merits alone, but my obsession with Spider-Man will quickly prove me wrong. (Sidenote: I still have not seen Spider-Man 3 out of fear my heart will be broken.)
When I heard about the Harvey Milk movie coming out, I was very pleased, and I wanted it to be good. I wanted it to be so stupid good that it infiltrates every aspect of American culture for a week. I wanted it to be Twilight.
I haven't actually seen it for myself, and I probably won't even get the chance to for a long time, but I was happy to read some positive reviews. Here's Metacritic. And here's Roger Ebert. They don't suggest that this movie will "infiltrate every aspect of American culture for a week"** but they are positive. And I can't explicitly recommend this movie, because like I said, I haven't seen and won't for a while, but doesn't it sound like it's worth seeing just to see?
*I don't remember who said this, but it wasn't me
**I do remember who said this, it was me, two paragraphs ago.