Streets of London, Willie McBride, Fields of Athenry, ...
A few years ago at one of my sessions, I proudly delivered John Martyn's "May you Never", followed by "October Song" only to be told that many years ago they had put these songs on the IAF list, (Interesting As F***)! That was me put in my place!
I also occasionally make the mistake of thinking that because I had had a good response to one particular song, that I could sing it every week!
There is usually nothing wrong with these songs. If they are crap to start with, they will be forgotten very quickly. Most songs have a time and a place and become so popular that everyone seems to want to sing them. Many of the singers obviously like the song, but not in the way you first liked it... Eventually you find yourself wanting to slit your wrists/go for a crap/test the tuning of your guitar/have a sleep, whenever someone starts up the song.
Strangely enough, there are often (though not always) actually quite good songs which just don't work any more. One of my favourite examples of this is "The Fields of Athenry". If you start this song up in a Glasgow pub, you can start a fight, or be thrown out. It's a great pity, because it's really not a bad song, and it's a great tune, but it has become associated in Glasgow with football fans of a certain persuasion. Some day maybe it will become generally acceptible once again, but not for some time I fear.