I had an incident a year or so ago when I was wearing my prescripiton sunglasses as I had broken my specs and being late on the STN-PIK I wanted to sleep. Hence contacts out and sunglasses on in the dark. Now in London no one looks twice at things out of the ordainary but on arrival at PIK, I had one of the staff in the dayglo yellow announce loudly to his mates at the gate "Here, luk at that daftie wie the sunglasses on." What he did not expect was me to turn on my heal and yell back at him but before I could retrace my steps he was off.
I asked to see the Duty Manager at the Information Desk but the disinterested woman couldn't understand why I needed to see someone and said "She was airside and might be back in a few hours" They're crap at customer service really...
Long story, short story, I emailed some people and made it damned clear that as a paying customer I expected a minimum degree of service and not some muppet having a go. The gentlemen was identified on CCTV, questioned, and since he was already on a warning, dismissed.
Never be afraid to check the name badge, ensure they see you do it, write it down, and walk away without ever swearing.