Dealing with tough customers doesn't always have to be challenging. The first thing is to make sure that they know that you're listening to them and that you sympathize with them and that you're relatable, that you're human. You get upset too, and what's upsetting them may upset you as well. So you want to make sure that they understand that you're on their side and that you're there to help them. Letting people talk allows you to identify certain needs. Just probing a little bit more, why are you so upset today? What happened? Tell me. And just by breaking down that defense wall, you can get a lot more information out of them and possibly even cross-sell them something else that can fit their needs that they may not even know that they had in mind.