A "phone flu" epidemic has hit Singapore hard.

In the bus or train, many are glued to their smartphones or tablets. Young (or even older) couples in restaurants text intently on their phones rather than talk to each other.

Young parents keep their toddlers occupied with a tablet, rather than play with them.

Pedestrians nearly collide with obstacles, as their eyes are on their phones, not on what may be in their paths.

How many of us have sent e-mail messages to a colleague two doors away, instead of going over to have a conversation?

In addition to the "reserved and undemonstrative" nature of Singaporeans expressed by Ms Maria Loh Mun Foong (Courtesy begets courtesy; March 21) and the "poor upbringing" mentioned by Mr Jeffrey Law Lee Beng (Basic courtesy begins at home; March 22), "phone flu" - our obsession and pre-occupation with our smartphones - is a big reason for the reduced courtesies we see in daily life.

Our need to be constantly connected to the virtual world reduces our humanity.

It prevents us from noticing the magnificent tembusu trees silhouetted against a blue sky.

It shuts us out from the wonderful chatter and laughter of children playing at a playground at dusk.

It also blinds us to the efforts of elderly aunties and uncles clearing tables in the foodcourt, and of migrant workers slogging in the midday sun to beautify our parks and improve our roads.

So, let us greet the bus driver on our next trip, switch off our smartphones and enjoy the ride by noticing the world and the people around us.

Tikki Pang (Professor)