banana skin vs tribulation

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. 

tribulation

noun
  • Any adversity; a trying period or event. 

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