"Rules of the Game" - Relationship Metaphor

Any relationship could be described as a rollercoaster, for they have their uphills (good times) and downhills (bad times).  The relationship between my oldest brother, Nick, and I can be related to a rollercoaster.  Since he is at college, I rarely get to see him.  Sometimes when he does come home, he tries to boss me around, so we end up fighting most of the time.  This would be the downhill.  Other times he will be nice to me and even offter to give me a ride somehwere whether it's to the football games, practices, or a friend's house.  These times would be concidered the uphills.  All in all, the relationship between my oldest brother and I is like a rollercoaster because we have ups and downs just like a rollercoaster.