If you could accomplish only one thing during the rest of your life, what would it be?

When I'm old, if I can look back on my life and say, like Paul "I have fought a good fight, I have finished my course, I have kept the faith"; if I can live a consistent christian life, loving my neighbour and presenting Jesus to others as often as He gives me opportunity without shame or hesitation, being a faithful witness unto the end, that would be it.