Rotation keyframes don't play back right

Ok, so let’s say I want to rotate the camera on just the X axis. I insert the first keyframe, move to 20 frames later, hit R+X and rotate the camera, insert that keyframe. Well, when it plays back, it ends up at the correct final rotation angle, but the way it gets there is wacko and not on the axis I selected. Why is this happening? Thanks

Rotate by how much? Blender sees first key frame and next key frame, 20 in your case. It doesn’t see in-between what you did. If there is several ways to get there, Blender will do what ever it sees reasonable.

So if you want to nail the movement down, add more key frames. Or, edit the curve in Graph editor.