Why is life often bittersweet?

Life has been described as a wild rideon a rollercoster and that certainly describesmy life and for me if is often bittersweet!!! The following is a snap shot of a typical week: Sunday: Our phone is not working and the repair            man walks in while I am in the middle of            a bad agruement with my sons."I had be            come furious with them after they disrespected            me verbally. I could of died of embarrassment!! Monday: I was having a deep and meaningful discussion             with my co-worker when my boss tells me the             city inspector she has been expecting for six whole             months and on whose behalf she has been torturing             us has arrived. We got a great mark dispite the sticky             table the inspector put her papers on and that I had forgotten             to clean!!! Wednesday: My boss suddenly decides to give me a week of vacation next                   week and I am grossly under prepared!!! That means no breaks                  for me as I scrabble to finish things.Thursday: My boss is off and it is not stop stress at work as I prepare for                 Halloween and being off next week. My student asks for her evaluation                which I had completely forgotten to write.The work and the children                get to me and I feel deflated and exhausted at the end of the day.Friday: WHAT A DAY!!! HYPER AND SICK KIDS, A BOSS WHO ALMOST PUT HER           SELF IN THE HOSPITAL, DEADLINES AND TONS OF MESS TO CLEAN UP           AND LAST BUT NOT LEAST KIDS TO TAKE TRICK OR TREATING AND            ACQUAINTANCES TO MAKE SMALL TALK WITH!!! Today: The day starts when I find my Beloved cat which I have had for eighteen years dead. Well back to the rollercoaster of my life.................peace and friendship to all!!!