I'm a bit late replying to this but there are some dreadful standards creeping in. A recent find by a geocaching friend of mine was a glove - yes, that's right, the cache was a disposable glove. The co-ords were way way off too.
I am relatively new to geocaching, having only started in March 2011, but I try to do it right and try to get tips from veterans. A bugbear of mine is when I go to check on my own caches only to discover that one finder has decided to move the cache to a different hide! Close by but not my own hide.
Another bugbear is terrible spelling mistakes and grammar in the descriptions / titles eg the use of 'of' instead of 'have' and wonder instead of wander, but perhaps I am being too picky there.
Also, there are a number of cachers who want only easy caches....to my mind that's boring. It's nice to have some easy ones but it's great to have a whole range of difficulty.
Worst of all though are the cachers who are unfriendly and are annoyed with you if you might get FTF before them / refuse to go for a joint FTF.
That's my rant over! Perhaps I should end on a more positive note? I could say lots of good things like how some of the experienced cachers have helped me such a lot with advice, support and encouragement, even passing on their own telephone numbers if I should need advice. Also, how friendly most people are who you meet on the cache trail and how great it is to meet all the friendly people and share a find.