Do not walk up to people and say, "Smile, sweetheart!"
1. I am not your sweetheart.
2. I do not WANT to smile, asshole. For a plethora of reasons. Mostly because I'm at work, but there are plenty of others you aren't privy to. Suffice it to say, I'm not always extremely happy. Glasses are half-full and chipper people who think otherwise annoy me. I will be cordial, even pleasant, with you, but forgive me if I don't have a shit-eating grin on my face.
3. You are so getting decaf.