TM, I used to say that. (cowering to corner now....I have since been educated - not once, but twice)
My mom says "this too shall pass", too. Drives me crazy. So do kidney stones, and while you're sitting there enduring that wonderful event in life, you aren't saying "this is all gonna be just GREAT!"
Recently, she told me I just need to adjust my attitude. I went on a tyrade last week after difficult child's second suspension. Basically, I verbalized what we all feel a good chunk of the time - "is this gonna be worth it?" I live in a very old house, I drive very old cars, all to give difficult child the best shot I can.
Boy, did I get a new behind out of that one... Sheesh. I survived difficult child 1 for 15 years. I am onto difficult child 2. 17 years of difficult child's and 12 to go til this one's an adult (and we all know that's a magical number in which children are no longer difficult child's who wreak havoc on their parents lives....) I'm entitled to one night of griping about it.