lol, we all make mistakes. I think I saw Phil Ivey say once that he has never played a perferct session and makes at least one mistake every time. Keeping the mind focused for a long period isn't that easy, especially when you enter a comfort zone of having a large amount of chips.

I did a similiar thing the other day in a SnG. I was playing solid poker, winning pots, staying out of trouble. There were 5 of us left and of the 13,500 chips in play, I had 6,000 of them. The others were fairly evenly spread amongst the other 4 who ranged from 1,500 - 2,000 chips. At this point I should have just cruised into the money but my mindset changed. When I looked back at this SnG I realised my playing style definitely changed when I had such a big chip lead. I started raising with marginal hands, chasing straights and flushes without getting pot odds. Trying to bully other players when I had nothing. Suddenly, there were 4 of us left and I was the short-stack!! I literally threw away my chips and I couldn't recover. I went out in 4th and just missed the money. I was both amazed at what I'd done and also angry with myself for doing it.

The main thing is to identify where you went wrong and learn from it