You can understand French when someone speaks at 0.01 mph, which is approximately...no one in France. You've studied French, so when you're in Paris, your friends expect you to understand even the most muffled metro announcement (and you can't).

If someone asks you to order at a restaurant, your voice still gets soft and shy so the server knows you've studied French enough to be respectful but not long enough to come at you speaking like zjsuzjsüzjszhjzsé after all you said was, "Je prends un verre de vin, s'il vous plaît."