I also examine our family and community events with a similar eye to "how sustainable is this?"

Upon proposing to my (now) wife in the early 90s, I promised her that she and our prospective children could fly back to Seattle 1-2 times per year to visit with her family. We do this every August and every other Christmas to uphold my promise, though she's aware that the time will come that such trips will be much less frequent (and may eventually cease). During the August vacation, most of the in-laws spend considerable time water skiing, after hauling the boat 100s of miles (and over one range of mountains) with a vehicle specifically purchased to have lots of boat-hauling power. I politely refrain from the sport, after many episodes of arm-twisting to get me ski (and one daughter has chosen to refrain as well, though the other is an avid advocate).

One teachable moment occurred when someone asked how far my 2000 Honda Insight could travel on the 35 gallons of gas used in a particularly active day of skiing and lake touring. I responded, "from Washington DC to Seattle", which caught some people by surprise; the contemplative looks lasted more than a few seconds... and then I mentioned that it could amount to 7000 passenger-miles in my 12 person vanpool, followed by more reflective sinking-in. But eventually the conversation shifted to some other topic, and everyone went back to 'normal' in their energy consumption patterns.

There are other struggles too, when the wife suggests that we go visit friends by car who are hundreds or even thousands of miles away because "we haven't seen them in a while" and her email chats with them invariably end with "we simply MUST get together soon".

The family car is a Prius, but I'm acutely aware of extra miles that could be induced by "it's more efficient, so we can go more places". She's aware of Peak Oil, though doesn't want it to interfere with 'normal' travel habits as long as it is affordable.