I keep the autonomy on and I usually concentrate on one Sim and the others will do whatever they want. I've also had saves in which I put random Sims with different traits living together and I never clicked anything, I just watched them doing their things. There used to be a lot of deaths and fights between those Sims, but never a romance. It was entertaining, but it was difficult not to click anything. I don't have those saves anymore.
Right now I have to play with autonomy off on selected Sims because there is a bug that makes Sims drop everything from their queues. I hate to do it, but there is no other choice if I want my Sims to do their work tasks etc. I hope the bug will get fixed soon.