I thought about this for a bit and remembered several more silly things which I have either done, or which have happened to me in various games.
In my first playthrough of Blue, I failed at going through Rock Tunnel. I did not have Flash, I did not know how to get it (or that it even existed), so I had to try to go through it blind. I remember that I reached the end, but I somehow didn’t find the exit, so I thought I had missed it or gone wrong somewhere. I then went back throughout the entire Tunnel again, eventually finding myself back at the beginning instead of reaching the end.
Later on in that playthrough, I failed to receive the Poké Flute from Mr. Fuji since my bag was full. My English wasn’t very good at that time, so I did not understand why I didn't get it (I am pretty sure I just missed it completely). I wasn’t sure how to continue, but I decided to try my best. I had been stuck at an earlier point in the game, and then I had mostly just stayed in the same areas without backtracking. Now, I decided to try something different. I explored everywhere I could go, biked around through all parts of Kanto that I could explore at that point. Eventually, I ended up talking to Mr. Fuji again without a full bag, and got the Poké Flute from him so I could wake up the Snorlax and proceed.
One more thing from my first playthrough of Silver. I encountered Sudowoodo, but since it was a roadblock Pokémon and there had been two Snorlax in Blue, I thought there would be at least two Sudowoodo in Silver. So I defeated the Sudowoodo, but since there wasn’t another one later on in the game, I never got to catch a Sudowoodo in that playthrough.
Let's fast forward a bit. Around ten years ago, I was chatting with a friend on a Pokémon Xat. I was wondering if he had any suggestions for a nickname for a Gyarados (then a Magikarp) which I was planning to raise on B/W. He suggested a nickname, but his keyboard derped and what he wanted to write became “Acuggalo”. I thought it was funny, so I decided to actually use that as the nickname for my Magikarp. Sadly, I don’t think I ever got around to actually raising that Magikarp, but I think I still have it in one of my games somewhere.
I also have another story about a different Magikarp in Gen 5. I was RNGing the gift Magikarp in Black 2, but I managed to screw up a bit as I had selected one seed for the IVs but another seed for the PID (which also had the correct IVs). Then I did my PID advancements, but I still got the Nature I wanted since it turned out that both of the seeds I used had the same Nature after the same number of advancements.
Next, some more stories from Battle Facilities. Last year, when I was trying to beat Super Multi at the Battle Subway in Gen 5, I met a lead consisting of Metagross and Krookodile. The Krookodile used Earthquake, damaging the Metagross. Then, the Metagross used Magnet Rise! My opponents had a nice strategy there, too bad they didn’t take the speed tiers into account.
Earlier this year, at the Battle Tower in Sword, I was playing Double, facing a Cramorant and Ludicolo. The Cramorant used Surf and caught a Pikachu in the process. The Ludicolo then also used Surf, damaging the Cramorant to the point that it fainted (it had taken heavy damage before) and fired its Pikachu Missile at the Ludicolo, which got paralyzed! That was hilarious.
Lastly, two battles against Leon (also in Double) where he tried to “predict” my next move by switching out one of his leads for Charizard. But this failed, since I used a different move compared to on the previous turn. In both battles, his Charizard got OHKO’d on the same turn as he sent it in, meaning that he never got to GMax it in either of these battles. So that made these battles rather unique.