Who are the 'wild men'?

[Kuruharan]

Originally Posted by Elmo

Gondor conquered swathes of Rhun and the Harad as well. Small wonder men from the Northern Waste to the Southern heats turned to Sauron to drive out their Numenorean oppressors.

Which begs an interesting question of what life under Sauron's domination was like?

Tolkien spoke of the Easterlings and Haradrim being relatively primitive until the Numenoreans and Sauron (under pressure from the Numenoreans and desiring to have tools at his disposal to compete with them) started uplifting their material culture. I suspect the Numenoreans and Sauron both only wanted to give them so much to help them, but only so much as to prevent them from getting "ideas."

I wonder, was serving Sauron a choice that the ordinary Easterling or Haradrim disliked and regretted or did the two not seem so different to them?