Actually, I've done several things over the course of September so far (and another thing back in August the result of which is still not in my possession, so there's that) that I probably shouldn't have done on account of having a negative amount of money.
I bought my own copy of Guild Wars 2, I kind of went on a book buying spree (apparently I have no self control in bookstores--actually, I must have little, or I would've walked away with way more overpriced purchases) last week and never even bought the book I was there for 'cause I thought it was too expensive, and now I've just bought tickets for the Davis Cup.
Because I am an idiot. So, yeah.
PS - The dentist ended up costing just under €400 which is just insane.