Sneaking up on 50!

What is the big deal about turning 50?

I guess, for me - it is the acknowledgement that:

a. my life is surely more than half over,
b. there are certain things a 50 year old body does not want to do
(and can no longer do!),
c. it is becoming increasingly difficult to appreciate RAP music,
d. we are responsible for our choices and their affects,
e. the majority of "stuff " we consider a big deal - is not big!,
f. people who think they know the only way to know GOD scare me,
g. the sun will come up tomorrow!

How about you - what do you think is the "big deal?"