Not a copyright or trademark expert, but seems like if it's a generic
term like "That's Just The Way It Is." and you write it like a generic
term and not in quotes and capialized as I just did, then you should be
OK. There's a couple of published writers more familiar with
issues like these, you might try emailing your question to them
directly. Jamesritchie, Georganna Hancock, bobkalsey, Linda
Adams.
Also, you might post this in the Q&A forum. I got good
response there to my question on running into other authors fictional
characters in my story.
Keep writing,
John