The opposite of responsibility is blame. Customers may be angry about other things, but you think they're just mad at you. Customers have other problems beyond broken machines or service needs, and may be taking those problems out on you. Your friendliness and willingness to help is in direct proportion to your success. Your reputation is there before you arrive.
Service is a feeling.
If you can make 'em laugh you can make 'em buy. Don't give the customer a bunch of lame excuses or reasons you can't do what they want. Give solutions, not excuses. Own the problem, own the customer, lose the problem, lose the customer. Personal principles precede company policy.