I am invisible

This is something I've suspected for some time, but now I'm quite sure. People barge into me, jump in front of me in queues, walk through me (almost). Today, I was waiting at the door of a shop which is exited by a short flight of stairs. I stood to one side, holding the door open, while two elderly women climbed slowly up the stairs and out into the street. No eye contact, no word of thanks. Nothing.

I don't expect bunches of flowers or even flowery language. In fact, I don't expect anything of a floral nature. But a smile? A "thank you"? A recognition that I'm there, perhaps?

No. I'm invisible. I must be. So look out. Soon, I could be somewhere near you, watching your every move, and you'd know nothing about it at all. In fact, I could be standing behind you right now.

So if I am, and if you're offering, mine's white, please, with no sugar (red if it's wine).