I also agree with PH.
last years worst hive harrass's at 20 yards whilst approaching them before opening the hive, and looked like a dalmation whilst opening.
I collected them from an Urban location in Southampton from a chap on the forum who was threatening them with a petrol can.
To deal with it, I divided the hive into three and combined them with NUC's.
None of the present hives are considered 'gentle', but are now good hardworking hives which are easily tollerable. I am happy.
Two years ago I did the same, and last year the main hive turned out to be my most productive hive by far.
I caught a huge and truely savage swarm late last year, which I am currently dealing with, and so far have only split them (The BKF member Freefall has met them!).
I do not have a problem with grumpy bees, and sometimes there is a reason for it (I had a very defensive hive that was being invaded with red ants. got rid of the ants, got rid of the temper)
The location of my grumpy hives are in a blind field, with thick set haw and bramble hedgerow and barbed wire around the field. The hives can be seen quite clearly down the hill at the opposite end by the entrance (36 acre rectangle). This is not a place 'someone' can go accidentally.
As PH rightly says, apiary situations are different, and just because someone cannot tollerate grumpy bees in their back garden, does not mean someone else is not in the position to tame them. (and I enjoy the challenge!)
Everyone should think of their location carefully, and hives often turn grumpy for periods for genuine reasons (wasps, ants, old queen etc).
I do not believe that it is a good message to send for new beekeepers and lurking preservationists, that experienced beekeepers reach for the petrol can JUST because they are not cute and cuddly as they would like them to be....