1. Get an Octopus card for MTR trips and small purchases at convenience stores, regardless of how long your stay in Hong Kong will be.
2. Tipping is not a must, as many restaurants already add a service charge to the bill. If not, HK$20 is usually more than enough.
3. Small talk is not really part of the local culture. So, don’t take it personally when your “hellos” don’t get a reply.
4. Gifts are important. Always hand them over despite polite refusals in the beginning, and never unwrap in front of the giver.
5. Smoking in public is not always allowed. Much in the same vein, public displays of affection are certainly not encouraged.