Traveling with friends can be your worst nightmare. It may sound like the ideal situation when you think about partying together in Mykonos or swimming in Thailand, but once you're there, it's an entirely different ball game. Between differences in budgets, personalities, living styles, and priorities, your travel experience could be completely ruined by your friend—whether that's because you're dragging your drunk friend away from a sexy stranger or skipping meals after spending too much money on last night's dinner because your friend wanted to go somewhere "nice." When it comes to ruining friendships, traveling with a friend can do more damage than living with one.