Because they have absolutely no morals or values.
They are so self-entitled to everything.
They are so ungrateful.
They are so unpatriotic (some won't even stand up let alone sing or know all of the words to their national anthem).
They don't show much respect or appreciation for their heritage and/or cultural values.
They want the best of everything right from the start.
They think brand new things are better than second hand.
They don't know how to fix anything or improvise (they just say it's stuffed and buy a new item).
They don't know how to save money (forget about their virginity, they throw that away asap).
They don't know what a descent, honest hard day of work is.
They believe that only between the hours of 9am and 5pm is the only time they can work.
They expect every ailment known to human kind can be fixed with a pill or antibiotics.
They expect the highest wages for the least amount of effort.
They don't have passion for what they do anymore.
They don't know how to budget.
They live beyond their means (credit card debt, mortgages etc).
They disrespect their bodies in so many ways with excess alcohol, drugs, smoking and even food.
They don't know where most of their food comes from, let alone understand how it is grown and processed.
They don't know how to cook properly (opening a packet of something, heating it up in an oven or microwave is not cooking; neither is pouring boiling hot water over it).
They don't know how to light a fire without paper or matches.
They are so absorbed in fashion trends, fads and stuff like that as a result of tv and advertising.
They waste so much time, effort and money on beauty products and bodily enhancements (breast implants and tattoos come to mind).
They don't have any respect for the elderly, those in authority or the laws of the land.
They think that they are above the law.
They aren't disciplined.
They try and manipulate and justify bad behaviour or outcomes when they are caught out.
They think they are right all the time, even when proved wrong.
They are never sorry; just sorry that they got caught out this time.
They are so self-righteous.
They believe what defines them as a person is their university degree, job, possessions, how much money they make and in some instances how many people they've had sex with.
They are so quick to reach a judgement about anyone and anything.
They reject so many compatible people in their lives based on looks and status.
They think they are experts on everything because they read something about it on google.
They aren't generous or charitable.
They have no faith or deep concept of spirituality.
They don't understand what commitment is and what it takes.
They are always looking for and wanting to know if there is a way of opting out of something like an 'exit clause'.
They waste so much time, effort and money on pointless pursuits like facebook, computer games, pornography and gambling.
They don't know how to spell properly let alone form sentences that are grammatically correct.
They don't know how to plan ahead for anything; shopping, travelling, having children etc.
They believe that the main requirements of caring for a child are buying everything it wants and entertaining it by sitting it in front of a television, computer or allowing it to play with a mobile phone.
They don't know how to change or repair a car tire on their own.
They don't know how to correctly jump-start or roll-start a car.
They don't understand that cars require maintenance; radiator coolant and oil levels need to be checked every couple of weeks.
They think the wearing of seat belts in vehicles should be optional.
They think that they are capable of driving and texting at the same time; NO YOU ARE NOT.
They think they have the right to drive under the influence of alcohol, drugs and other narcotics.
They think that driving and owning a car is a right; NO; it is a privilege.
They think they have the right to street race or do burnouts on public roads.
They think that they have the right to travel faster than the speed limit.
They believe that they are invincible in their fancy cars with ABS, airbags and side curtain bags - umm you can still die in a car crash with those things if you are speeding.
They use profane language too freely in inappropriate circumstances and situations.
They lack patience.
They lack common sense.
They wouldn't know how to cope without electricity, natural gas, fossil fuels, running water on tap let alone their other technological gadgets.
They think it is so important to have traveled the entire world.
They succumb to peer pressure too easily.
They justify many actions with the stupid response, 'everyone else does it'.
They seem to think that the answer to every problem is dictated or resolved with their sexual anatomy.
I could go on forever!
Any wonder I can never get into a relationship with a descent woman these days when everyone else is so screwed up; sometimes I think I was born in the wrong time and era.
Great question!