Priceless!!
I can only echo my colleague's post.
When I am in uniform it is not unusual to get an upgrade. I don't expect it but it is always gratefully received.
While easyJet don't have business class, more often than not I'll get a crew cup of tea and some water. (Luton base).
I know what it's like to meet grumpy and surly pax, so I do try and be as pleasant as possible. A smile and a thank you costs nothing.