"There are thousands to tell you 
it cannot be done,
there are thousands to prophesy failure,
there are thousands to point out to you
one by one, the dangers that wait to assail you.
But just buckle in with a bit of grin,
just take off your coat and go to it;
Just start to sing as you tackle the thing
that cannot be done',  and you'll do it."- Edgar Albert Guest, poet

Before you do anything,
if you do not want to waste your time,
you must first ask yourself, "Do I have what it takes to do this thing?
if you do not have it, do not do it.
If you do, you will not learn anything from it.
It will be a total waste of your time.

You can do anything.
But if you can't, do not deceive yourself.
And if you want to get things done,
do not listen to people who are not doing
anything. You need doers around you.
You want to be around positive people,
people who want you to succeed.

Because they know that 'it can be done.'
Because they believe 'it can be done.'
Because they have done it.