I should probably make an effort to finish that game someday. Not that I've finished many Super Mario games. I think I've purchased every one, but have complete

I should probably make an effort to finish that game someday. Not that I've finished many Super Mario games. I think I've purchased every one, but have completed maybe two of them. So many levels incomplete... I wonder if game devs feel bad working on higher levels, knowing only a tiny portion of players will actually ever see them?