Yea I've failed the the past 3 jams I've done but each time I've managed to get closer and closer to finishing. Honestly like what menicafolden said above just start with a concept so simple that you might even think it's overly simplistic, but just try and make that first. And from there just keep building off and transforming a seemingly simple idea into a complex one! Even if you don't have the time to make it more polished or complex, well hey atleast you got a game. Good luck on your next jam hope ya do well.
For me, i feel it's the opposite (not only for jams, but from everything, really): I tend to do great the first time i'll do it, and then i'll just do worst and worst, get really sad about it, and then... quit
This is the first time that i openly talk about it, since i really like making games (it's a thing that i always wanted to do, and one that i want to transform into a job, if i can manage to do it) and i'd really like to not end up like everything else end up so far...
As for the the "concept part", the answer is pretty much what i've already said to menicafolden: that's exactly one of my struggles. I've kinda liked the last part of your answer tho. :3
Thank you, i hope good luck to you too, and thanks for the kind words!!!