For every problem, there is a neat, plain solution...and it is always wrong.
For every vision, there is an equal and opposite revision.
Four-wheel-drive just means getting stuck in more inaccessible places.
Free advice costs nothing until you act upon it.
Free time which unexpectedly becomes available will be wasted.
Freud's 23rd law: ideas endure and prosper in inverse proportion to their soundness and validity.
Friends come and go, but enemies accumulate.
Frustration is not having anyone to blame but yourself.
Genius is 1% inspiration, and 99% perspiration.
Geologists do not dress for success unless they are trying to convince others that they are going on interviews.