Check out the thread (up to 13 pages of replies so far) under this forum category called Spellcasting in PVP where you can enjoy reading a friendly, lighthearted discussion on the matter amongst users who clearly respect each others' differences in perspective.

There are a few tangents, but the posts worth reading in my opinion are the ones debating auto-attacks interrupting casts, vs GCD/instant abilities which require input on behalf of a user to be able to do the same.