There are various customs surrounding handshakes, both generically and specific to certain cultures:
The handshake is commonly done upon meeting, greeting, parting, offering congratulations, expressing gratitude, or completing an agreement[disambiguation needed]. In sports or other competitive activities, it is also done as a sign of good sportsmanship. Its purpose is to convey trust, balance, and equality. If it is done to form an agreement the agreement only offical until the hands are parted [6]
Handshaking in this situation is not about etiquette. It implies agreement. He bows in respect, because Leung is the chief executive of HK, Wong didn\'t shake Leung\'s hand because they stand on different grounds.