This thread has now reminded me that I did in fact see the last airbender in the cinema, not knowing anything much about the source animated series at the time I could tell it kinda sucked, but it lost that extra level of suck thanks to my ignorant bliss. My friend who dragged me to see it wasn't so lucky, and now having seen the animated series I know his pain.
Yet, YET
The most bored I have ever been in the cinema, is without a doubt Terminator Salvation, I've seen worse movies but they're at least fun to riff on from shit like Blood the last vampire's live action thing to big names like Rise of Skywalker
But Terminator Salvation, as someone with zero investment in the franchise, was the most plodding boring piddle I've ever seen in the cinema, I don't even know how people and especially fans feel about it (it might be like, an underrated cult classic for all I know), I just know I wanted to get out of there and do anything else.