How do I tell my mom to stop being so ungrateful?

My mom complains more than any person I know on this earth. She complains that she works soooooooooo hard at her job and is sooooooooo tired, yet she is a claims auditor at an insurance company where she literally sits down at a desk and types information from papers to the computer...that's it. She voluntarily took over my aunt's job at delivering and making orders for AVON...but she complains about that too. She has a great life. She works at a high paying job that a monkey can do. She comes home to a clean house everyday (I do all the chores around the house) and good food (my dad and I do all the cooking) She never does any real physical labor yet if there's the slightest chance she has to work more than she wants...it's "the whole world is on my shoulders" I am sick of it. I'm in college paying my own way and working my own job and my dad has his own job too but we never ever complain. And she's always like "you guys couldn't understand what I'm going through" what is there to understand???????? I want to tell her "You think the world is supposed bow down and wait on you hand and foot? you have an easy life!! you know how many people would love to have your life and all you do is complain?" It makes me sick to listen to her. But she gets so angry if anyone says anything to her about it