Beginners who come from Mudcat can be recommended to listen to French 19th century operas first, or perhaps to the cherished "Bartered Bride" (though they may object against some clichés in that one).

The first operas I got to like were 20th century ones - Bartok's "Bluebeard's Castle" and Stravinsky's "Oedipus Rex". Wagner's "Tristan" wasn't far behind. All of those have simple, archetypal storylines with close to zero historical or political connotations.

19th century French opera has never really connected with me. It just seems like a bunch of songs strung together.