A required visa in itself does not have to be problematic? I have been to (for me) required visa countries like Russia and China without any problem. Cannot eve

A required visa in itself does not have to be problematic? I have been to (for me) required visa countries like Russia and China without any problem. Cannot even remember I applied for visa (but it shows required here, so I guess I did - both were some years ago). At worst its just a bureaucratic process. But I guess its difficult for some countries. So adding some indication of the difficulty to get visa for the 'missing' countries would certainly add value.