Eh, There are many reason movies can improve (Or become less enjoyable) with further viewings:
A screaming brat or otherwise obnoxious audience member distracting you on your first viewing
Watching it the first time with someone who doesn't like it and makes comments can color your first viewing, and seeing it again, without them can allow you to see it with unbiased eyes
You may have been distracted due to a heavy "real life" burden or tragedy on your first viewing
You may viewed it your first time on a "low vibe day"
you may have gotten up to use the restroom or grab popcorn at an important point in the movie on your first viewing
You may have had a life altering event since your first viewing of the movie (IE: Maybe you thought some guy who got dumped was an idiot and acting unrealistically and ruined the whole movie for you, and then 6 months later you get dumped and understand exactly what he was going through and realize it was very realistic and well done when you see it again. There could be a million different scenarios here for life altering events that change your world view and make you see things you hated in a new light)
The list of possibilities goes on and on.