Quote from a fortune cookie in my office cafeteria:
"People who are late are often happier than those who have to wait for them".

Seems like the premise around which the interesting concept of "Indian Standard Time" is built.This doesnt refer to a time zone.It refers to a state of being. When someone tells me that they will meet at 6:00 PM , I know that I wont see the person till 7:00..and no explanation offered/required. It may be very odd for someone unaccustomed to this culture [and sometimes annoying for people accustomed to it too...], but thats the way it goes.

This habit is changing. and its for the better I feel.Take for example , a North Indian Wedding. The marriage vows will be exchanged somewhere during the early hours of the day. I mean 1:00 AM !! . Now the brides family waits for the groom to show up in a traditional procession called the "baraat". The wedding/reception commences when a baraat arrives. The wedding invite may say that the baraat will arrive at 8:00 Pm..but that can mean that the grrom may show up at even 9:00 or 10:00 PM..Imagine the frustration caused to the brides dad [He swallows it as it is a part of tradition], and the hunger pangs consuming the guests :)