Co-incidentally to the recent thread on "A Dive Safety Rule: The only one
you'll ever need", a friend, (Richard Taylor) just posted me (some of!) the
lessons that diving has taught him.  He gave me his permission to share
them.

Strike

1.  Every dive is optional.  Every ascent is mandatory.

2.  If you pull the deflate hose the surface gets further away.  If you
press the inflate button on the BCD, the surface gets closer.  That is,
unless you keep pressing the inflate button all the way up, then you
finally pass the surface and it gets further away again.

3.  Diving isn't dangerous.  Drowning is what's dangerous.

4.  It's always better to be up here wishing you were down there than be
down there wishing you were up here.

5.  The ONLY time you have too much air is when you're on the surface.

6.  The regulator is just a big valve at the top of the tank used to keep
the diver cool.  When it stops, you can actually watch the diver start
sweating.

7.  Learn from the mistakes of others.  You won't live long enough to make
all of them yourself.

8.  The probability of survival is inversely proportional to the speed of
arrival at surface. High speed of arrival, small probability of survival
and viceversa.

9.  Never let  your dive gear take you somewhere your brain didn't get to
five minutes earlier.

10.  Always try to keep the number of ascents you make equal to the number
of descents you've made.

11.  There are three simple rules for making a no bubble deco dive.
Unfortunately no-one knows what they are.

12.  You start with a bag full of luck and an empty bag of experience.  The
trick is to fill the bag of experience before you empty the bag of luck.

13.  In the ongoing battle between bubbles made of air expanding faster
than flesh and blood, the air has yet to lose.

14.  Good judgement comes from experience.  Unfortunately, the experience
usually comes from bad judgement.

15.  It's always a good idea to keep the regulator in your mouth as much as
possible.

16.  The three most useless things to a diver are the spare cylinder on the
boat, computer with no battery and those missed deco stops back in the
water.

17.  There are old divers and there are bold divers.  There are, however,
no old bold divers.