Since when being a gentleman has become an offense ?

My parents raised me to be respectful to everyone, to children, to young men, to young women, to older men, to older women, and to everyone and everything in between. And to do so not searching for approval, but because I believe is it the right thing to do.  

You know, like holding the door for someone, or letting someone pass before you in a line up because you judged that maybe they are in hurry, or they looked tired, you know that kind of understanding that stems from living with people and being a person. 

But lately ( may be the last 10 years), I keeping living, or witnessing situations where acting in a nice way is frowned upon and looked at with the eyes of anger, or simply ignored and not even a thank you is being giving a sign or gratitude. No don't get it wrong, being nice is not about seeking gratitude, but gratitude tells a lot about a person, for a person with no gratitude is the worst type you can be around.

And to the risk of raising that sexist debate, I see this kind of behavior among younger woman more than any other age group. 

Anyone else noticing this change in societal interactions or have an explanations to why it is spreading ?