Frankly, this does not sound like a JFK quote. This doesn't even feel like a JFK quote. Perhaps someone has taken Internet liberty and license to attribute this to him. "One person can make a difference, and everyone should try." John F.
"Do not pity the dead, Harry, pity those who live without love. This is a fate worse than death. Living without love is worse than living without your soul. You are fully sane and love evades you." -Albus Dumbledore tells Harry in the afterlife, HPatDH
What lies before us and what lies behind us are small matters compared to what lies within us. And when you bring what is within out into the world, miracles happen. - Henry David Thoreau (my favorite quote!