How exactly am I controlling trajectory/attutude on crafts with no control surfaces or vectoring?

[Rangoon]

As a curiosity, how is it that I am able to steer vehicles without control surfaces or thrust vectoring? Is in place for gameplay purposes as a simplification? Or is it implied that there are always micro control surfaces even on a solitary command module? Is my Kerbal pilot shifting his weight in his seat to get the craft to precision tumble?

[Red Iron Crown]

Reaction wheels. KSP's reaction wheels are a good bit more powerful than real life ones, but that's a concession to gameplay.

Welcome aboard!

[Rangoon]

Reaction wheels. KSP's reaction wheels are a good bit more powerful than real life ones, but that's a concession to gameplay.

Welcome aboard!

Brilliant! Thanks!