A half dozen under the “other” category:
Forgot to bring ski boots when driving to ski area (to meet up with a visiting Pugskier/Ski Talker) and had to rent boots for the day.
Forgot to bring a ski jacket, had to go into the ski shop and buy a hideous neon ski Burton shell that was 2 sizes too big. That said, it was decent quality so I wore it for a couple years, including to my first Gathering.
Forgot to bring ski pants (I would typically change into ski kit at a changing room at one of the lodges). I went to the ski shop and bought a pair of shell pants, luckily they still had a couple in my size.
Got my backpack strap caught on the seat of the chairlift and at the top terminal I was spun around the bull wheel (fixed grip chair) before it came free. At which point I went sprawling. I’m sure it was amusing to someone.
Was on a button lift and let the platter slip between my legs and I was holding onto the tow with my arms most of the way up.
I haven’t usually left gear in the parking lot, but I have several times left my phone in the car, and had to walk back to get it.
Wait: 7, I did in fact check boots as luggage. It was a non-stop flight on a less-than-half-full flight during Covid so I figured less chance of getting mishandled. It worked out OK. And I would do it again.