Ticket cancellations

Travelers need to be careful about cancellations or  no shows.I recently found out that it is better to cancel the sector if you are not flying,rather than have it lapse as airlines tend to impose a no show charge,and I thought that having paid for a ticket,it is my privilege whether to travel or not ,but apparently the airlines do no think so.
Their stand is as follows:
a)If you do not show up-they can likely impose a no show charge on you.
b)They will not refund unused sectors
c)They and the agents may likely impose a cancellation charge.
So if you book a ticket ,it is best if one travels.
My recent experiences are based on Air India (Tried to cancel an Ahmedabad-Mumbai Sector) and British Airways London-Singapore sector.
Apparently for all these airlines passengers are the last consideration.
Another long standing grouse is:
While airlines allow online reservation-they do not allow online cancellations.,the human intervention for cancellation can be a painful experience.
Even a signature event like TIECON makes cancellations very painful,while reservations is online cancellations is via the admin office of TIE Silicon valley which takes its own time to cancel which is a painful process.