Has flattery or sucking up ever backfired on you?

I am about to do a very ass-kissy thing. I recently asked a question about a letter of recommendation for an award I am going up for.

I really want the award. I think I am a good contender, but I also think everyone who is up for it is a good contender, and there isn’t much to differentiate us from one another.

The award does not require any kind of personal statement, but I am going to include a letter to the selection committee anyway, basically thanking them for considering me and telling a short anecdote. It is true that I am grateful they’re considering me, but let’s face it, I am only doing it in the hopes it will give me even a tiny competitive edge.

So it got me wondering, has any kind of ass-kissery ever backfired on anyone? Did you think you were going the extra mile, but it turned out to be overkill? Feel free to comment on my specific situation, but I am really interested in hearing what your experiences were.