What makes a Seller happy?

I've noticed that there are several topics on here asking what Agents offer you as a seller.

However, I want to know what sellers really want so I can provide them with the best possible service and we can discuss different ways of making this happen.

So what makes you as a seller happy or on the flip side what have agents done in the past that have really disappointed you that you never want to happen again?

I hope that this can help us all a little bit to make our buying and selling experiences that bit better.