Forbidden to cross the sea
I did not understand why it was forbidden for Raman-noodle to cross the sea. There were some Indians sitting next to me so I asked one and he said "I don't know. Ask my dad" (I shoulda known a young kid would not know;-). Anyway his dad told me that since Brahmans are at the top of the caste system, they can not cross the sea because everywhere else is "impure". Someone else ytold me it was sometimes even true for rivers.
What I did not understand was whether it was crossing water that was bad (sea, river) or just leaving India (or their particular area of India) in general.