Bad manners are never excusable in any walk of life. No difference for an officer of the law.
Never yet met a copper who was anything other than great, just one very lazy one who turned up 8 months late to criminal damage so his boss would let him move jobs.
Agreed Richard - I have only met this one over many years, and I am not ashamed to say that I made it my business to ensure his superiors were aware of the fact (as I have when met with particularly good service from an officer)
It is important to always remember this country operates on a principle of "policing by consent" and the goodwill and respect of the public is vital to that undertaking.
I think the police do a very important and difficult job - and just as we should remember that they may have had a bad day, so might the member of the public they exist to serve. Courtesy and respect is a mutual requirement.