I find this movie to be very confusing...
Basically I find it really hard to follow because before the title sequence starts, Joel has had his memory erased, and then after the title sequence, he hasn't yet, and it's now in the past, when he goes to the book store and Clementine does not remember him.
Is this right? But this is where I got lost for the entire rest of the movie, cause there is no transition from present to past at all. All there is, is a title sequence in between and I assumed it was still the present for the rest of the movie.