DWYT is good!
Here's another that has been used:

From Prime Suspect's Geo-lexicon.
DPM – Including the letters “DPM” in a cache log was a once-secret way to indicate the cache was of low quality. DPM is an abbreviation for “des palourdes mortes", which is French for “the dead clams”. The entire French phrase is “Les longs sanglots des palourdes mortes blessent mon coeur avec un languor monotone pendant qu'ils dansent à minuit", which translates to “The long sobs of the dead clams wound my heart with a monotonous languor as they dance at midnight”. The idea was to include this phrase in a cache log to clue in others that the cache was of low quality. Rarely actually used, as the meaning of DPM quickly spread throughout the geocaching community, and its secrecy was lost.

Jared Ross wrote:

Anyone else have any ideas or comments on how we can improve the caches in our state? Maybe we need a special acronym. Instead of TFTC we could have DWYT (Don't Waste Your Time). Of course we could always start using this website to generate log entries for us: http://loungingatwalden.googlepages.com/RandomLog.html
My favorite generated log entry: "This cache was ill-conceived and ill-received. You should turn your GPS over to the nearest authorities! TNLN and almost didn't bother signing the log!!"