Being English and being constantly exposed to bad language practice (not the curse word type), during a recent trip to Switzerland, I totally failed in keeping my English plain and vanilla. Their English was better than my own and in this sense I totally failed. Here is my top five of innocently said statements that just do not translate. If nothing else, it might help you to not make the same mistake when presenting to others not of your own tongue.
1) Shooting fish in a barrel
2) Stuck under a rock
3) Lots of ways to skin a cat, including with a machine gun
4) Everything including the kitchen sink
5) More features than you can shake a stick at
Speaking English is really hard to do when you’re English!!!