What I find annoying is when people send trades, and then simply leave a message such as "I have a few of your Wishlist pets."
...Well, couldn't you save me the time/effort and add them yourself? o.O
And my "Precious Canines" tab, when people offer ridiculous trades for them. I worked hard to get them, trading a lot of my advents off for them, and I'm not gonna give them away for something that I have. >=(
I've had players offer me 5+ pets for simply normal, current month pets that I already have/could trade for easily. *facepalm*