One of the joys of travelling is spotting the weirdest signs on display purely for my viewing pleasure. Upon entering the Khumbu Valley in Nepal I had to stop at a checkpoint where a member of the Nepalese Army spent about 15 minutes perusing my various documents in an attempt to decide whether I was to be allowed to start the climb up into thin air. He was carrying a very antiquated rifle that looked as though it had seen service in the Crimean War. As the soldier fumbled around with my papers, the muzzle of his gun was wandering all over the place and often ended up pointed right at my face. To avoid the chances of an unfortunate accident I wandered off to have a look at a nearby building. I was glad I did. On its wall was a sign welcoming visitors to the Khumbu Valley and warning them about their behaviour while here.

"Visitors," the sign urged, "must refrain from taking life, refrain from anger, refrain from jealousy, refrain from offending others and refrain from taking excessive intoxicants."

Well, that's my holiday buggered, I thought. Then I went through the commandments one by one.

I was pretty confident that I could refrain from taking life. I assumed the sign was talking about wildlife, as opposed to humans? I had no intention of bludgeoning a red panda to death just for kicks, and both yaks and yetis would kick my arse anyway so I was OK there. There was the occasional temptation to push the really keen, show-offy trekkers off a high cliff. When they storm past you, hardly puffing, with their professional trekking poles and heart monitors, you just want to give them a kicking, but this was too energetic an activity at high altitude. No, the most likely person to take a life was the soldier and his swinging rifle.

The only time that I was angry was on a particularly steep climb towards the end of the day, when it was getting chilly. This anger, however, was not something aimed at anybody around me. It was more an internal anger at the thought that there was an airstrip at the top of my climb and, had I known about it, I could have flown there and not had to do this knackering walk.

The jealousy thing was not going to trouble me, but I had seen a lot of it aimed my way. Having decided that trekking wasn't really my bag and found that you could rent horses in the Himalayas, I was in heaven. Other trekkers, however, were green with envy... or it might have been altitude sickness, it was difficult to tell.

Refraining from offending others was going to be the trickiest. I have an offensive condition: I can't stop myself offending people in a Larry David kind of way. I'd be in a bar 5km above sea level with people I'd just shared a big adventure with, and I'd go and put my foot in it by saying something stupid. This is one I couldn't avoid and I knew it. I wondered whether I should go and own up to the gun-toting soldier. I decided against it, as he was busy reading my passport upside down.

I checked the last urge for restraint – the no taking of excessive intoxicants. I liked this one. It was leaving me with the option of deciding what constituted "excessive". I had to be careful, though – another sign nearby warned trekkers to be on the lookout for signs of altitude sickness. One of the giveaways was "walking like a drunkard". Then I realised that the only cure for altitude sickness was to be carried down to a lower altitude. Result. I could get totally pissed, stagger around, and someone would carry me back downhill to bed. I like trekking.