Namaste or namaskar is used as a respectful form of greeting, acknowledging and welcoming a relative, guest or stranger. In some contexts, namaste is used to express gratitude for assistance offered or given, and to thank the other person for his or her generous kindness.
Excavations for Indus civilization have revealed many male and female terracotta figures in Namaste posture which are believed to be dated between 3000 BC to 2000 BC. That's a long time to be greeting/thanking!
I'm currently being the best Hindu I can be and getting some good meditation in whilst being thankful for those around me. I'm currently at 15 days; what's your 'record' for being thankful spoonies?