Problems with mesh looking wierd

In a scene I’m working on, I just plain create a cube/cylinder, delete the top face and then extrude those vertices around in 3d space and then subsurf it and this is how it turns out. The error, however, occurs before the subsurf, so if I remove the subsurf, the faces still look strange.

I have tried recalculating normals outside, turning doublesided on/off, and here comes the strange thing: I also tried creating a similiar mesh in another (blank) blender project and that one did not turn out like this.

If someone could pinpoint the mistake that would be great! Thanks in advance.

EDIT: Oh, and it also does not occur when only extruded along two axes, but when I start moving those “vertex rings” that makes up the cylinder joints around in the third axis this happens.

At least now I figured out WHEN the problem occurs, but I still don’t know why or how to avoid it.

When I extrude the edge of the cylinder (in this case) or box which I also tried, it works fine, but when I rotate the newly created circle or square made up by the extruded edges is when it turns out wierd. Even if I just rotate it to the slightest degree.

Fixed it! As it turned out, it was my blender version that fucked it all up. I had some sort of unofficial build, but when I downloaded the official one (though still being 2.42) it just worked.

Just so you know if you ever see that again that looks like duplicate objects or verts in the same place.