I've been asked quite a few times by other pilots and students about my interpretation of SOP and adherence to them.
I tend to liken SOP to the Green Arc on (pre NG) intruments. Operations within the arc provide a generally stress free pleasent flying envirnment. Actions expected and understood by all involved.
If circumstances require one to action outside the Green Arc in the Yellow band we will not immedietly self destruct, but we'd best have a very good reason for going there and be sure both the reason and action are well understood by all involved. The Red Arc would be Negligent, Malicious and suicidal flying (ass kicked out the door if you survive stuff).
All that said, like the guage, it's only as good as it was made. I'm quite lucky in that our SOPs are well thought out, logical and easy to follow but I do understand some airlines SOPs are subject to political interference (internal and external) and wierd personality inputs.