United or England ? Scousers do this type of thing , the reason it's a thing ( which it isn't ) is because England are shit . I support both , I love both , there's no conflict as far as I can see. United have given me far more joy than England though .
If you want to know how you should feel , you'd be better asking real madrid , PSG , Bayern , juve , Ac Milan . Those guys win stuff domestically and internationally .
I don't know how they'd respond , but I don't think it would necessarily be along the lines of ,.. feck italy it juve all the way for me .