What is the perfect global planetary climate?

I'm rather fond of the Hadeon Eon myself, although molten lava and 450 degree F air temps tend to discourage visitors. If you have a space ship capable of time travel the impact that created the moon is quite exciting.

I prefer visiting the waterfall that created the mediterranean for day trips though. Shirt sleeve weather. Watch out for the megafauna though, they are not tame.

Presumably the one society is adapted to, i.e. the one we had during the industrial revolution. Is this some sort of a trick question?

One where all forms of the planet's inhabitants are able survive to their normal full term. Currently not the case on planet Earth!