Ever had a run that was technically winnable, but you just lost for whatever reason?

First post on this sub, or actually in general, and I was just curious: ever had a run that you probably could've saved, but chose not to or only realized later?

I've been trying to do a run with every single evolutionary family to build up Candy and get more ribbons. Earlier today, I got a Pidgey run all the way to the final boss but nothing I tried seemed to be working and I couldn't be bothered to reset a thousand times to find the right strategy.