I think it's a little unbecoming to critique the minor interactions of someone's life, and make it a fixed part of their character, yeah, that sounds pretty cheap and petty, but does that happen every time? Or did the person just end up the victim of some very weird, but very typical couple's argument? or a bad day, bad week, bad moment.
It's never cool to be disrespectful to people who are working, I agree, I rarely am, but I am sure if I was internationally famous, it would happen, from time to time. To have your every interaction examined, under the glare of social media's unforgiving nature would be unbearable for anyone.
For example, I get a coffee everyday, usually same spot, pay cash, I usually tip generously or reasonably, sometimes if I don't have 1$'s, I don't, I just hand a $5 and keep it moving. Someone records that like, this cheap a$$hole doesn't tip?!
My boy did tell me a story from like 2005, of working a concert, and he said J Lo wouldn't even look at anyone, but Marc Anthony was high fiving and backslapping the whole walk out of the venue LOL
but Marc was coked up all the time