Which movies do you think had really lousy special effects. I'm thinking of early Sci-fi movies mostly, but any you can remember. MST3K shows lots of them. You should also consider the state of the art at the time. Say Ray Harryhausen is an example of doing the best he could with what tech he had, so I'd say his were good. Here's a couple off the top of my head. Plan 9 from Outer Space: Bela couldn't save this one from the grave. Where are the aliens? Rocky Horror Picture Show: The special effects were cheezy, but perfect for the camp!
The 1953 movie “It came from outer space” seemed tacky to me, left me flat with no 3D effects. 12 years later I was in an aerial photogrammetry class and discovered I had no depth perception. My eyes didn’t work together…never had, never would. The aliens never would leap from the screen for me. That explained why my baseball game frequently saw me getting the soft ball in the face as my eye switched from distance to close. It also meant that many of my classmates would get job offers from the Company….the CIA company for work in the early days of of the Viet Nam war doing air photo interpretation. Give my vision handicap I would not get a job offer from the Company.
Check out Nemesis from 1992, starring Olivier Gruner. The final, stop-motion animated battle against the titular cyborg looks pretty hilarious. Actually a pretty decent movie until that final bit.