In rock climbing, friendships can come under enormous strain. The late UK Alpinist, Roger Baxter-Jones, once created 3 rules for those going on a Himalayan expedition. The 1st rule was, simply and poignantly, 'Come back.' The second rule was, 'Come back friends.' The 3rd rule was, 'Top out,' i.e. Reach the peak. Rock climbing is psychologically exhausting as well as physically