I've had two genuine 'true' UFO sightings. Maybe another couple, but just these two remain unexplained.
Years back, I was with two friends and we were looking into the clear night sky to see a satellite or the MIR space station pass over. We saw a satellite/Mir and just watched it as it passed overhead. The trajectory of the satellite passed another light that was also moving. We started watching it and were baffled. This light moved in a triangular path. It moved clockwise on an equilateral triangular path! The satellite continued on it's path and we just focused on this weird light that remained in the same place we originally noticed it. It seemed to be right out there on the outskirts of a low Earth orbit, but who can say?
We watched it for a few minutes and turned the air blue with, "What the f*** is that?!" and similar comments. This light carried on repeating the same motions. It didn't do anything apart from move in the triangular motion. We got bored and walked on...what else can you do?
The next one occurred a few years ago. It was the year Shakira's album was on heavy airplay rotation. I was in Eastbourne, England. It's on the South Coast on the English Channel. I was at a party. Me and three mates had a walk across the road to the beach. It was around 23:30. We were talking BS and having a laugh. Maybe 30 metres away there was a group of some 20 goth/emo types. The sky was totally clear and star-studded apart from some wisps of cloud. Suddenly from the northern horizon, a red light zig-zagged across the sky silently. Again, the air was turned blue with 'fucks!'
This red light zig-zagged from the north and shot across the English Channel over France at a hell of a speed. It took around 4 seconds to cross from north horizon and disappear over the southern horizon. Damn fast!
The group of people further down the beach saw it too and were swearing like us. We were fairly excited about it and headed back to the party. That Shakira album was still being played lol. We burst in and told them all about this 'UFO sighting' and got laughed down! Some thought we were hoaxing and others said we'd been drinking and imagined it all.
I've had two other odd UFO experiences, but they're not as compelling as those two. One was a sphere that faded/vanished as soon as I noticed it....possibly imagined it? The other was with 6/7 friends around 5am when a blue 'flash-bulb' light lit up the area like daylight for a second or so. Both of them could be some mind-fart incident.
EDIT TO ADD: During the European airspace shutdown following the Icelandic volcano. Got out my car and noticed an orange ball of light travelling east silently. It struck me as unusual...colour wasn't like anything I recognise from police helicopters etc. I reached for my phone to record it and couldn't find it. Went inside and forgot about it. A few days later, some guy posted a thread on ATS about seeing an orange ball of light travelling east. The time he saw his light was some few minutes after I saw mine and I live due west from where he lives in Yorkshire. I posted a response, but you all know how forums are...