Hi Pucho812,
To me, mono recording uses a different set of skills in the performing and recording : to get a good end-result, it was necessary to have a good balance in both frequency (by the use of suitable instruments in the pop world) as well as positioning and dynamics. No fancy techniques such as panning during the performance to distract/entertain the listener. Even in multitrack-land, I think that mixing down to a mono master requires greater effort to get the balance right.
As the other guys have said, try listening to mono from a single speaker: it is different to that from a pair of speakers with the mono image between them, but you may have to do so attentively.
Happy listening
Mike