Offence or Harassment - also giving offence, is the noble art of offending people. Squaddies are particularly renowned for their unnerving ability to cause maximum offence to the maximum amount of people in the minimum amount of time.
This can be achieved by the simple expedient of opening one's mouth after fifteen pints of wobbly and expounding your deeply-held views on a range of issues on homosexuals, mongs, tree-huggers, lezzers the Dear Leader and Nu Labour (to name but a few) on any unsuspecting civilians that may be in the near vicinity.
Further offence can be caused by airing various parts of the anatomy in public. This can be as innocuous as waving your arse in the general direction of passers by to playing elephants and asking unsuspecting civvies to comment on the quality or length of the trunk in question. Deep offence can be caused by the public display of behaviour normally restricted to the barracks such as skiffing or playing Freckles.
Certain quarters of society take offence very easily. The simple act of waving, smiling or merely acknowledging their presence with a curt nod can result in a reciprocal acknowledgement in the guise of a tirade of venomous vehemence dripping with vitriol. And heaven help you if you even mention 'him' in the wrong context.