I can't think of one particular moment, but there a a number of things.
The thigh rub! OUCH. Having to wear tights in Gran Canaria in July, just to TRY and releve it!
Being asked to get off a theme park ride.
Having to ask for an exstension belt on a plane.
Sitting on a chair with sides, having to wedge yourself in, so when you stand up, the chair is attached to you!
Going to attractions and not knowing if you'll fit. (I wouldnt go to Wookey Hole caves on holiday just incase there was a really small cave and I wouldnt fit!)
Weak looking furniture always scares the life out of me!
My life will be so much better when I'm thin!