"If you woke up breathing, congratulations! You have another chance!"
no, this one is better:
"If we all worked on the assumption that what is accepted as true were really true, there would be little hope of advance." Orville Wright
my personal favorite (still on trial, don't take it for granted yet

"It is a funny thing about life: if you refuse to accept anything but the best you very often get it." W. Somerset Maugham
for less ambitious people:
"If you can get nothing better out of the world, get a good dinner out of it, at least." Herman Melville
still working on my personal message...