My father always uses the word "challenging" instead of saying things like frustrating, negative, unfortunate, or multiple other ways of describing difficult situations. I have done this myself for as long as I can remember, following his example, and I think it has made a huge difference in my life. I read this quote by Carlos Castaneda today and it reminded me of my father:

"The basic difference between an ordinary man and a warrior is that a warrior takes everything as a challenge, while an ordinary man takes everything as a blessing or a curse. The trick is in what one emphasizes. We either make ourselves miserable, or we make ourselves strong. The amount of work is the same."