I am always frustrated by the boarding time printed on the the boarding passes,
I have yet to see an AC flight commence boarding at the time indicated.
If the airline regularly commenced boarding at the time requested on the boarding pass,
I think passengers would eventually start to arrive at the gate in proper time to ensure
on-time departures. Other airlines seem to be able to offer a correct boarding time, and
enforce things such as " gates close 10 minutes before departure".

I think it would just show respect to the passengers if AC actually commenced boarding
at the time it says it will.