In the offices of a major imaging company lives a hat. On the hat is marked the word Twat in large embroidered letters.
If you have made a particularly stupid mistake in your work, you are made to wear the Twat Hat for an amount of time commensurate with the scale of the stupidity.
This has given rise to the phrase 'I've just had a Hat Moment' and similar.
'Hat moment - I've just shut down the wrong server.'
'Pass the hat, I've been a twat.'