banana skin vs deep water

banana skin

noun
  • A cause of difficulty, or potential embarrassment. 

  • The outer skin of a banana, especially once removed from the rest of the banana, which may be slippery if stepped on. 

deep water

noun
  • A difficult or embarrassing situation. 

  • Waters suitable for deep-draft ships, especially ocean-going. 

  • Used other than figuratively or idiomatically: see deep, water. 

How often have the words banana skin and deep water occurred in a corpus of books? (source: Google Ngram Viewer )