True story:

I went to a Catholic high school and a couple of times per year the parish priest would come in so that we would do confession. It was all a fixed routine. We, at least the boys, would all give the same set of "sins":
- I don't listen to my parents
- I sometimes disrespect my teacher.
- I sometimes 'abuse' myself.

A few Hail Mary's and all was good.

Then one year a different priest was sent. My friend went in, my turn was after his, and he came out very red-faced. The new priest had never heard the phrase 'I abuse myself' and he thought my friend was into some sort of self-mutilation and kept asking my friend to explain to him what exactly he did to himself.

Needless to say we all adjusted our phrasing so we wouldn't need to explain ourselves.