Here's another favourite - it always makes me pause and reflect on whether I know where I'm going...

The Road Not Taken

Two roads diverged in a yellow wood,

And sorry I could not travel both

And be one traveler, long I stood

And looked down one as far as I could

To where it bent in the undergrowth;

Then took the other, as just as fair,

And having perhaps the better claim,

Because it was grassy and wanted wear;

Though as for that the passing there

Had worn them really about the same,

And both that morning equally lay

In leaves no step had trodden black.

Oh, I kept the first for another day!

Yet knowing how way leads on to way,

I doubted if I should ever come back.

I shall be telling this with a sigh

Somewhere ages and ages hence:

Two roads diverged in a wood, and I –

I took the one less traveled by,

And that has made all the difference.

                                         – Robert Frost (1874–1963)

And this is another of my favourite poems. It's also an integral part of a very inspiring movie that I've enjoyed watching (Invictus).

Invictus

Out of the night that covers me,  

  Black as the Pit from pole to pole,  

I thank whatever gods may be  

  For my unconquerable soul.  

  

In the fell clutch of circumstance         

  I have not winced nor cried aloud.  

Under the bludgeonings of chance  

  My head is bloody, but unbowed.  

  

Beyond this place of wrath and tears  

  Looms but the Horror of the shade,  

And yet the menace of the years  

  Finds, and shall find, me unafraid.  

  

It matters not how strait the gate,  

  How charged with punishments the scroll,  

I am the master of my fate:  

  I am the captain of my soul.  

–  William Ernest Henley (1849–1903)

Here's one of my favourite poems, modified slightly at the end - it's 'IF - the female version'. Yes, the last line doesn't rhyme, but it's impactful all the same...

If  (the female version)

If you can keep your head when all about you
Are losing theirs and blaming it on you,
If you can trust yourself when all men doubt you,
But make allowance for their doubting too;
If you can wait and not be tired by waiting,
Or being lied about, don't deal in lies,
Or being hated, don't give way to hating,
And yet don't look too good, nor talk too wise:

If you can dream - and not make dreams your master,
If you can think - and not make thoughts your aim;
If you can meet with Triumph and Disaster
And treat those two impostors just the same;
If you can bear to hear the truth you've spoken
Twisted by knaves to make a trap for fools,
Or watch the things you gave your life to, broken,
And stoop and build 'em up with worn-out tools:

If you can make one heap of all your winnings
And risk it all on one turn of pitch-and-toss,
And lose, and start again at your beginnings
And never breathe a word about your loss;
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"

If you can talk with crowds and keep your virtue,
Or walk with kings - nor lose the common touch,
If neither foes nor loving friends can hurt you,
If all men count with you, but none too much;
If you can fill the unforgiving minute
With sixty seconds' worth of distance run,
Yours is the Earth and everything that's in it,
And - which is more - you'll be a Woman, my daughter!

                     -  Rudyard Kipling (1865-1936)