'Piss me off' is a very every day comment. Not shocking at all. However i would not say it in my Mother's company, nor my little boy. On a forum - yeah.
'Crap' is something i made a post about, my little boy got in trouble for saying the word and they called it swearing. It isn't to me.
Take no notice of her, who ever she is.
Be really 'grown up' and call her a
NINCOMPOOP which is my favourite word