If I accidentally sit down on a chair or bench in Risen 1, I'm stuck. There seems to be no way to get up again and I have to reload my last save. I can't remember having any such issue in Gothic.

There must be a way to escape these evil pieces or furniture. But how?

Thanks, that was it! I had configured the controls mostly for keyboard use (because laptop and I don't always plug in a mouse) and didn't think to try the mouse buttons.