Couple of evil ways to improve your customer skills
1. If it is difficult to refrain from shouting back at angered customer and escalating the conflict to the seismic proportions - think otherwise. Stay calm, defuse opponent’s anger. After all - you always can work on a more elaborate scheme to get back at the bastard later - revenge is a dish better served cold.
2. Try to treat any customer’s representative as a person who can make a decision to fire you on the spot. Even if it is just some seemingly obscure and downtrodden intern.