Deadpool: I made it about half way through and had to turn it off. The characters were unlikable, the humor felt soulless and manufactured, and I don't even remember what the plot or conflict were supposed to be. Maybe it gets better at the end, I don't know.
Bridge to Terabithia: This is mostly forgotten as far as I can tell, but the fact that this didn't go down as one of the worst high-budget movies of recent decades along with the likes of Battlefield Earth or Movie 43 still tells me it's still vastly overrated. I went to see this for a friend's birthday party and there were a grand sum total of two reactions from everyone in that theatre: crying or uproarious laughter. It was truly shocking as a member of the audience, even as a kid, to see how badly that movie handled the last half hour or so. If you want to watch a somewhat similar, but I believe very underrated movie, check out the Last Mimzy.
National Lampoon's Christmas Vacation: I really don't see why this has become part of the Holiday Canon. I don't think there's a single moment I laughed when watching it. It feels exactly like one of those sequels that are solely made because the last movie turned more of a profit than the execs were expecting and the actors didn't have anything else lined up. Very Pirates of the Caribbean 4. Then again, I'm also weird in that European Vacation is probably my favorite of the National Lampoon's Vacation movies.
Absolutely agree with the last one. I was expecting a somewhat silly, but still laugh-out-loud film, but it was boring with very few funny moments.
