I've quit announcing that I'm tired. I hear the "yeah, I know how you feel. I'm tired, too" response too much.

For me, there is such a huge difference between just being tired and having the dreaded MS fatigue. If I do get the fatigue and someone comments on it or asks about it I tell them I have "MSF" (multiple sclerosis fatigue). It sounds more severe than just being tired (because it is) plus it shuts up the folks who want to play the "I'm more tired than you are" game.