Did anyone here other than Darkstar actually try searching the player up? He has a city in Odovakar that has triumphal arches, so I'm assuming that is the city he's talking about:
So he has 36 multistories and 4 clapboards which makes 3648 population. Since I'm too lazy to count and determine the happiness from the decorations and roads, I'll only make an estimate that the city was angry before he built the Arches (as a polished theatre and polished bath is still 1428 happiness under a normal city), so that likely did bring him up to a normal city (not delighted) and is currently 182 under delighted.
If the OP is sure that his city was not angry at first, then (as stated on my last reply) I'm assuming that some polishes wore off before the Arches were finished constructing.