Demand, and delight are different. Demand is you population, you must have that amount of happiness to receive 100% productivity, Example: 1000 pop, you need 1000 happiness. Delight is 120% productivity, and you have to have 1.4 times the population to receive that.
Yes, the smiley face is wrong, and it saying you are at 100% is wrong, the smiley face is a known graphical error, and should have been fixed long ago.