Some people are just to greedy and they don't know how to appreciate things in life. I guess things are just too easy to be attained and just too convenient for them to grab it and be ungrateful about it.
These people are also liars, great one indeed. They lie to others they lie to themselves. They always have a lot of excuses to justify their moronic actions and behaviours. They will even tell you they are grateful about everything they have, but the fact is they are not, not even the slightest.
Because in the deepest of their conscience, they have covered up their true selves. The nature of greediness, ungratefulness and ugliness as well as the stupidity have to be hidden, hidden behind the mask of hypocrisy.