Metaphors, cultural, regional, interesting?

Casting pearls before swine, Break a leg, drive safely, oh no wait that one is actually pretty self-explanatory. Metaphors, do they translate? Are there other interesting statements like this in your culture which would make as little sense to me? Metaphors is probably not even the right term. An Irish friend once told me it was better to have one goat in a pen rather than two on your roof. I needed an explanation, what would goats be doing on my roof. I guess, or actually I know now, that in the past they you sought for roofing and often times goats would climb up onto the top of the house and eat the grass growing on the roof, causing the roof to cave in so it was a very bad thing to have two goats eating your roof. Obviously, this I can understand it's better to have a little of something than to have more of something that's causing damage to your life. Now my question is this do any of you out there have a similar interesting sayings that we in United States might not have I've always been very curious about them and I would like to share them in my paper soap you have them please comment them or email them to me I would love to hear them thanks for your readership I appreciate it I'll see you soon bye.