Arg, I just lost about 200 coins because I used Hasten!
I was facing a level three (the Earth/Gravity one) and had all three of my Mindgates out. I could have beaten him but I keep him alive so I could steal and use all his Stone Skins (Rainbow deck; I had max Earth quanta) and increase my reward. In the end I had about 479/479 HP.
He was out of cards and would lose when I ended my turn, so in celebration I used all the cards left in my hand and used all my other abilities.
...Unfortunately I had 0 cards left (blame it on the Golden Hourglasses) when I went on my clicking frenzy. All I saw was the enticing flashing border, then suddenly a darkened screen saying I lost. I was petrified. 11 minuets of my life, wasted :c