Yes Life is a roller coaster. The moment it starts to run up, one could feel the thrill that one could shout out loud, an adrenalin pure. It is compared when one is happy or when one has success in life, at the top of one's carrier, be in love or with a joyfull family there is thrill and excitement.
When the roller coaster goes down...the thrill is slowly calming down. You might think you just made it going to the top. It is like of life's failure, disappointments, loss of a job, loss of love, when sickness comes, one longs to be at the top again.
It is life's happiness and sadness,
Life's success and failure,
Of sickness and good health,
Love and be unlove,
Life and death.