Expeditions into jungles or across deserts or raging oceans are never easy. However much we might romanticize the lives of explorers, when you are in the middle of an inflatable boat with 50-foot waves all around, you haven't slept for three days, or you have been struggling with an injury in silence for a week, it is the little things that count. Let me give you a couple of examples: once you get above 25,000 feet (7,500 metres) on a mountain, and the temperature drops to minus 45deg, if you don't get a headache - the kind that grips your head like a nut in a pair of pliers - then you're not human. Part of this is the altitude, part is the inevitable dehydration that comes from the thin air. So working hard 24/7 to keep hydrated is essential. The only way to get water, though, is to melt the ice. But at that height, at that temperature, melting enough snow and ice to drink can take hours. So try and look at all those sorts of moments as chances to distinguish yourself - and it is the kind, unselfish mountaineer who is loved and is often the real bedrock of a great team.