sad vs too bad

sad

adj
  • Soggy (to refer to pastries). 

  • Causing sorrow; lamentable. 

  • Of colours: dark, deep; later, sombre, dull. 

  • Appearing sorrowful. 

  • Feeling sorrow; sorrowful, mournful. 

  • Poor in quality, bad; shameful, deplorable; later, regrettable, poor. 

  • Unfashionable; socially inadequate or undesirable. 

too bad

phrase
  • It is unfortunate that. 

  • That's a pity; that's unfortunate. 

How often have the words sad and too bad occurred in a corpus of books? (source: Google Ngram Viewer )