Roommate situations can get muddled and messy real fast, especially when matters concerning money are involved. You'd think you could trust a friend in that regard, but don't be so quick to assume… people can unpleasantly surprise you, as made obvious in this tale of petty revenge. One man told his ‘roommate horror story’ to r/pettyrevenge, which took place many years ago. While in college, he rented out a room in the summer at a friend's apartment in Colorado. He wasn't aware that this ‘friend…