Civ 5

[Napoléon]

The key to being not thought a warmonger is to not attack cities other civs are friendly with. They'll hate on you if you attack their friends, and generally won't care if you attack their enemies.

Yeah, whenever I play you usually get one or two civs everyone hates (usually the Mongols or Persians as they're expansionist douchers) and then the rest of the civs will form a sort of 'alliance of do-gooders' who denounce the couple of unfortunate civs. The easiest way to make friends is to denounce the same people they do. The strange thing about denouncements is it usually impacts far more with other civs than the one you're denouncing. I've denounced civs before only to have them want to be friends a few turns after the denouncement wears off, whereas if you denounce a friend of someone, they'll seemingly remember this heinous act til the rest of the game.

As for your workers, keep using them, the cost of the upgrade won't really hurt you as your economy should be growing all the time anyway and the benefits of having improved worker tiles far outweighs the very small cost of improving them.