Played a game of Magic The Gathering: Commander with some work friends at lunchtime. Had a great time, I've played before but this was the first time I've played with my own deck, previously I've borrowed one from another player.
About halfway through I found myself thinking
"this is fun, I wonder what other decks I could get?"
"..."
"oh. oh no. no no no no. shut *that* thought down"
This is how I end up with no money and a house full of cardboard. Yikes.