I've seen 3 UFOs in my life. One that stands out I assume was ball lightning or some kind of discharge since it was a blueish orb that did a figure 8 around a streetlight. Friend saw it too and we scared each other about ooh a UFO!
Another was witnessed by my nana and Mom who had me take a look through binoculars at night. Something was way up in the sky and motionless (or seemingly so) but dark against the dark sky. Had eyes on it for about half an hour so not a very high flying anything. Geostationary satellite seems the best guess. But I assume those have a light of some sort.
Other's the most curious. Driving with my Mom she pointed out what she called a flying saucer so looking I must admit, I saw a flying saucer. But it was so 'flying saucer-looking' I've always maintained it had to be a deliberate hoax type thing. I've since seen similar things that were confirmed hoaxes via balloons and r/c aircraft like.
I've never seen anything I couldn't come up with a plausible explanation for.