I usually give a bit of a pass to really low budget movies I have seen (things on Sci Fi channel, looking at you now) because polishing a script, creating an effect, hiring actors who can act all cost money and if the money is not there it is 95% likely that you are making crap. Hell, the last real clunker I saw was "mega shark v giant octopus". And it was garbage, which I kind of expected. But it also made me laugh a little and have a good heckle.
Have more of a problem with things you can see are costing a lot and really don't have the "making do" excuse.
Bloodrayne was hideous (and how it got a sequel escapes me).
I was with The Happening right up until the moment they explain what the hell was going on. At that point I swear that I could hear a flushing sort of noise.
Battlefield Earth - good grief. Just... well, what did I expect from something based on L Ron Hubbard and pushed by Travolta. That was the one time in my life I had a private viewing of a film because I was the only one in the auditorium.