My two teenage sons are on friendly terms only half of the time. The family in the flat next door is welcoming, despite the occasional communications gap, but we are not about to go into business together. Hong Kong's lawmakers have been chosen to work for the good of our city, but ideological differences ensure that decisions are made slowly and often do not go far enough.
Given that there is discord at even the most grass-roots of levels, only the eternally optimistic among us would be foolhardy enough to suggest that large-scale global meetings have any possibility of coming up with meaningful deals.
The United Nations is eternally, but irresponsibly, optimistic. Time and again, it favours grand gatherings over negotiations among key players. Its climate-change summit in Copenhagen was bound to end in disappointment. A handful of representatives from the developed and developing worlds - the US, the European Union, China and India - would have made more sense.
Developing and developed countries had made their positions plain years before the doors of the meeting halls opened. The experience of the Kyoto summit in 1997, and subsequent rounds of talks, made for valuable lessons. Bilateral discussions between the leaders of the most polluting nations had, in the preceding months, failed to iron out differences. Putting representatives of 192 governments together in the hope that positions would change was, in the circumstances, pointless.
What resulted was worse than could have been hoped for. Developing nations did not get the binding emissions goals and independent verification mechanisms they had demanded. The final deal did not guarantee developing countries the amount of technological help they need to reduce carbon emissions.
China, the world's worst polluter, ended up being lumped in with the least troublesome, the tiny Pacific nations of Kiribati and Tuvalu. A last-minute push by US President Barack Obama to get Premier Wen Jiabao on board failed miserably.