Xan Brooks, a film blogger on The Guardian, has asked this same question a second time around, perhaps trying to achieve some fractal structure, or more likely just forgot. Anyway, it remains an interesting enough topic that it can be recycled ad nauseam.
My first real problem here, however, is why would anybody watch a film a second time if they didn't like it on first viewing? So the chances of this happening are serendipitous at best; perhaps a friend or partner wants to watch it and you don't have the conviction to pick something else, or possibly it's on TV and the remote control has gone AWOL. Whatever the reason, I suspect this scenario is fairly rare. Having said that, its rarity value may well make such events more memorable. Watching a film with someone who is enjoying it may shine a new light on it... or on your friend. So which films come out better after a second viewing?
The above blog has a lot of votes for Starship Troopers, which I can relate to. The film's satirical undercurrent often gets blasted away by action scenes, not unlike Robocop and Total Recall - all of them by Paul Verhoeven. Films are often sold as something that they are not, thereby misdirecting one's expectations. Once the disappointment evaporates then perhaps one can re-view the film without the marketing lenses.
I tend to avoid big budget, over-hyped films with a linear storyline as I just expect them to be puffed up like candy floss and bad for my teeth. Indeed the three Star Wars prequels come into this category. I grew up with the first three so telling us how it all began is just a very long and dull journey into the obvious. I later decided to give up on the thin story and to just enjoy the special effects. The Lord of the Rings trilogy is similar in that the crust has been cut off the plot and then filled with long tedious battle scenes - what happened to the relationship between the two magicians? These films seem to make more sense watching them with children, so assume that was the target audience. In contrast, the Harry Potter films have just enough wit and cleverness to keep the adults awake.
I didn't say this was going to be easy! But which films have you grown to appreciate after hating them on first viewing?