Life isn't a dream
 
This is a great quote for when things don't go like you expect them,or how you dreamed them:
 
"The best-laid schemes o'mice an men
  Gang aft agley
  An lea'e us nought but grief an' pain
  For promis'd joy!"
  - To a Mouse , Robert Burns
 
translation to recognizable english:
 
"The best laid plans of mice and men
  Often go awry
  And leave us not but grief and pain
  For promised joy!"