This is possibly going to be a weird thread. Bear with me.
When designing games, sharing work, promoting our stuff, a lot of us make a lot of mistakes. And that's just the way it works. And, I suspect, some of us make mistakes that others have made before, because the process of screwing up and learning from it is too opaque - or too buried in other stuff. So, hey, let's try changing that.
Share a story of something you did badly in design, release, or promotion, and the lesson you learned. It can be something you corrected, or something you didn't - but it must be something you learned from.
I'll go first, just to break the ice...
This is / was a game I worked on over a year ago. It had a climbing series of player-created traits, and a core mechanic involving d6s. We played games with it, locally, and it worked pretty well. So I decided that maybe others could give me some input. So, I waved it around on my journal, and on the Forge, talked to a few people, and did a bit more work... and the work stalled out.
The big mistake I made was, though I went to others to get their attention, and asked for their input, I treated the attention as the good part, and the input as if it was somehow an obligation. Which skewed my idea of who I was writing for.
Reflecting on this, I learned to be thankful for constructive input, but not to treat it as an obligation. I've heard awesome ideas people have suggested for my stuff, tried to acknowledge them, considered them carefully, and then simply not used them if they didn't fit. I would have felt guilty about that, once.