A lot of UFOs can be found...

Using this particular google image search:
www.google.com...

Of course I narrowed it down to "windshield glass" because that's the search criteria where good examples of this kind of damage are easiest to find. However the same type of damage also happens to household windows, plexiglass, clear plastic camera cases, camera lenses, lens filters, etc. Many examples of pitting, chips, and tiny fracture damage fit the commonly seen archetype of "metallic UFO" most commonly seen in pictures. The "UFO" seen in these pics is often both very bright and very dark with contrasting sides and fairly consistent geometric shapes. Lighting when it hits this kind of damage from various angles typically has the same appearance with a tint of both the sky and color from the surrounding scenery. Also these UFOs tend to go unnoticed while the picture is taken and are often to the side or blurry - yet that's something that will happen when the photographer is acting on the spot and not noticing that the window they're looking through or their own camera is damaged and will have artifacts in the picture.

And out of that image search, here's a couple that could make some really good "UFOs".
media.merchantcircle.com...
www.heritagecarwash.com...
www.mbusa.com...

I'm not saying that all UFOs with similar traits are chips, dings, pitting, scrapes, or cracks. But without access to the location or vehicle a picture was taken from or a good look at the camera gear, this kind of artifact is very difficult if not impossible to rule out. It's not just bugs, birds, and lens flares or refractions.

I'm still looking for good examples of UFOs, but other than the unfocused pinpoint of light at night, too many pics can reasonably be said to be caused by this common environmental phennomena of wear and tear on optical media. (And no, I'm not out to debunk the entire topic. I've personally seen two or three things that I couldn't identify flying around before, so I can't dismiss the phenomena - and thus why I have some interest. My scepticism on the forums comes from the fact that the pictures with UFO claims often just aren't good enough.)

Thoughts on this or some good personal examples where you thought you had a UFO and then realized otherwise?