1. two people trying to fit all their luggage into a trunk in a very small car..
  2. a stock investment. . some stocks are safer but give less return .. some stocks require a low initial investment but are not safe and can be a waste of time (but if it pays off, it can pay off well)..
  3. life.. but you have someone to share it with.
  4. swimming in the sea with high winds and rocks on one side and beach on the other.. you gotta be careful but still have fun.