From the epilogue of Jon Krakauer’s “Into the Wild”:
Still, the last sad memory hovers round, and sometimes drifts across like floating mist, cutting off sunshine and chilling the remembrance of happier times.
There have been joys too great to be described in words, and there have been griefs upon which I have not dared to dwell; and with these in mind I say: Climb if you will, but remember that courage and strength are nought without prudence, and that a momentary negligence may destroy the happiness of a lifetime.
Do nothing in haste; look well to each step; and from the beginning think what may be the end
Edward Whymper, Scrambles Amongst the Alps
One of my favorite quotes.