My biggest complaint is finding that items I've crafted in the stable to unlock animals are disappearing. I finish an item and have more than 1, then when I go back later, the item has rolled back to zero. It happens ALL THE TIME and I'm fed up with it!!!
My second complaint is when planting the required crops to beat a farm, it doesn't say whether they are water crops or not. I wish Zynga would identify the water crops in the requirement thing just like they do in the market.