Being a spoonie is that moment when you're grocery shopping, and your energy levels have run into a brick wall. You're just pushing the cart around, staring at groceries with glazed eyes, trying to remember what you need. You realize your mouth is gaping a little, and you're self-conscious. But then you think, "No, it's fine, people will understand. I'm sure everyone else is tired from shopping."
And then you look around, and you realize that no, no one else is tired from shopping. Normal people don't get tuckered out buying groceries. Most people don't get home from the store and barely manage to drag themselves to the couch. Healthy people have deeper energy wells.
Being a spoonie is realizing that buying groceries uses up all of your leftover spoons, every single time.