Here's something that's emerging, that I think, if you think about it honestly, you have experienced and observed.
In the short time since Trump won the election, people have become markedly ruder in their interactions with strangers.
It's noticeable.
It seems like a door has been opened for people to look at the world, a given place, THIS place, as an environment where the priority is to, "Get mine".
It's happening on the roads, in stores, in the work place, even in otherwise friendly social environments.  
The "Trump effect" on America is emerging as a lack of civility, or, more precisely, a lowering of standards of civility toward one another.
Say anything you want without consequence.  Insult anyone you want without consequence.  Step on anyone you want without consequence.  Get yours, screw the other guy, without consequence.
No place is this emerging rudeness more microcosmically apparent than at Costco.  It's a downright battlefield now days.  
Sad.  And, a Trump consequence.