Struggling to find the right measure word when I'm under pressure—is it always 'gè'?

I'm a false beginner who can recognize about 300 characters, but whenever I try to order food or ask for directions in Mandarin, my brain freezes on measure words. I keep defaulting to 'gè' for everything—people, books, cars. Will native speakers judge me for this, and is there a shortcut to memorizing these without halting my speaking flow?