of take so long to shake hands

I just witnessed a group of schoolboys exchanging a series of handshakes at the MRT station. They shook hands with one another and then they parted ways. Those handshakes are those that has pattern more than badminton. Completing 1 handshake takes about 7 to 8 seconds. There were 10 schoolboys in that group. That means more than a minute was spent doing those handshakes.