Why Indians come late to parties and Americans don’t!

(Note: Basic knowledge of game theory is required to understand this. )
I had one strange observation while I was going for my friend’s party yesterday. Everyone I asked thought of going 1 hour late to the party. This is how I thought that things are actually working in the background.

These are the typical observations in a party scenario.
1. Normal party time : 8 PM – 10 PM
2. If you come 1 hour late i.e. at 9PM you will leave by 10:30 PM
3. Since some people came in late so those who come at 8PM are forced to stay back till 10:30 PM
4. You don’t incur any penalty by coming late

Now if I apply convert this in terms of pay-off when Nitin (my friend) and I plan to leave for the party. This is what I will get.
Each cell indicates the loss in time. E.g. “-0.5” represents extra half and hour lost by Deepesh because Nitin came late to the party. Similarly "+0.5" represents and extra half and hour gained by Nitin as he came late to the party.

Now by using game theory we can see that (+0.5, +0.5) is equilibrium.

But then why do Americans come to party on time?
The reason is that observation#4 is not true for them. There is a penalty in terms of loss of face if they come late. If we attach some value e.g. “-2” to this loss and re-work our table the pay-offs look something like this.

Both the people “Ontime” is the dominant cell. So, now I think I understood why we are always late in parties ;-)