I've forgotten the term, but it's where you feel the controls in the game - like when you push up against the wall, you can feel the wall pushing back in your hands. The term is erogetics or something. It's synonym is kinetics-something.
This arcade stick tutorial is great:
But what it lacks is that feel, so that just by feeling, you can tell the stick can't escape its bounds. Visually the stick does this, but not with feeling. I think the feeling is necessary, so people can play a game without pushing their thumbs too far up or down, left or right, in moving the stick.
So, how do I make the joystick feel?