Plastic Man was also a character that I used to not be able to tolerate. BUt then I read some of the stories written by well known artists. Then I realized that when Plastic Man is written by an untalented writer who's struggling just to keep an audience mildly interested is not going to be able to pull off an effective comic relief and then Plastic Man will come off as strained and just trying too hard to be funny, because that's exactly what the writer was doing. It all depends on who writes a character.
Hell, I think someone like Allan Moore, Mark Waid, or Kevin Smith could make someone as asinine as someone like Snapper Carr or the Guy Gardner interesting and maybe even tolerable.