This happened over 40 years ago: I was barely a teenager.
I was at Windsor Park watching the team I supported: Linfield.
They were overwhelmingly on top in an Irish Cup tie when the other side, Ballymena, scored a breakaway goal.
I hadn't noticed there were Ballymena fans sitting in front of me - supporters could more easily 'mix' then.
One of them turned around using both hands to give me the 'V-sign' and venom flowed from his mouth. I punched him in the face.
My uncle, alongside, rightly berated me and I've never thought of nor done anything like that in the decades since.
One of the things I most dislike about football is the hatred directed at the opposition, fans or teams: Wigan's supporters against Suarez, Tottenham's against Terry or, entirely perversely, Blackburn's against their own manager, Steve Kean.
No matter the motivation, how do you think you'd feel on the receiving end?
Is it too much to ask fans to wise up? Concentrate on supporting your own team. Oh ... and Linfield won that game.