Just for fun: Unusual cultural habits in India and around the world

Diksha
Nice topic, Let me add

1 - Cats are highly unlucky in India if they cross the road ahead of you
3 - Its always grace period. We are kinda famous for not being on time

The Indian nod, side-to-side, when you want to indicate "yes".  I do it now.

The wiggling thumb-up sign to indicate that something is not good.

The rapid hand-open-and-spread shaking, especially at someone to mean something like "stop or quit" or "leave it."

The open hand with fingers straight out at someone to direct attention to or put emphasis on the person you are addressing.

The slapping of hands together into a namaste and yanking down to your chest to indicate frustration and get away from something irritating.

The facial expression of widening the eyes, curling your tongue underneath with the mouth open, and Indian nodding all at the same time.

I forgot...

Eating with the right hand only and serving yourself or someone with the left hand only (hygiene-based).

Giving or offering someone something (like a gift to a friend, money to someone) with the right hand only.  I even see many Nepālese touching their right elbow with their left hand while offering with their right hand, consonant with certain āratrika methods in a Hindū temple (the waving of a plate with a flame in front of a deity).  A lot of times, when I remember, I do this.  Right hand offering with left hand to right elbow.  Typically, I see people offering with just the right hand without the extra step.

Stepping into a person's house with the right foot.

Leaving what you feel to be a sacred place or a temple by stepping backward off the platform (above the top step leading up) with the left foot and touching the platform surface with my right hand to my chest.

If you have a Hindū temple in the house that has to face opposite the entrance to the bathroom, keeping the bathroom door closed at all (In general, such small temples face the east in many cases) times.