hmmm... here are the reasons I've came up with :
1) Cheaper than owning a car (as in road tax, parking, fuel, COE,
maintainence, etc..etc.. ) *note: some points might not be
applicable for high maintenance bikes like Harley Davidson or
Hayabusa Turbo *
2) Damn easy to park (No need to worry about parralel or reverse
parking in narrow or busy roads, just ride straight into the lot,
set the bike on its main/side stand and u are done! To go out, just
push the bike into position! )
3) No worries about parking space when eating at famous places (eg:
U are in Geylang wanting to eat Tau Huay: If u are a car driver, u
must find a space to park your car at the road side, and that often
requires u to park far away from the store. As a bike rider, u can
simply park your bike on the pavement(for a short while as u eat )
! )
4) Able to squeeze through traffic while cars remain stuck in a
traffic jam.
5) Can take short cuts through places too narrow for a car to take
(eg: back alleys )
6) U will be more aware of the traffic around and be able to judge
traffic conditions better u as u are in "open air " while the car
driver is in an enclosed area.
Add on guys! 
