"Dwitiya Vighnam" is a popular Hindu belief....if you 'start' doing something one day then you continue to do the same thing the next day. Say for e.g. I started blogging yesterday, so if I don't blog today then it's not considered a good start.
Dwitiya => secondVighnam => obstacle
I believe the real reason behind this belief is to encourage continuity. But I'm the kinda person who does something for 2 days to avoid Dwitiya Vighnam and then stops doing it the third day ;)