If anyone thinks (assuming) Mayweather wins to get to 49-0 and retire is crazy.

Heavyweight Rocky Marciano retired undefeated at 49-0. Mayweather wants 50-0.

The person Mayweather is fighting (Berto) has lost three of his last six fights.

Marciano was a heavyweight (even though back then he only weighed around 190 pounds). He will remain the only undefeated heavyweight champion.

I think Mayweather wants to be the "bad guy" in boxing. Mayweather and his father had not nice things to say about Marciano:

http://boxingjunkie.com/2015/08/31/rocky-peter-marciano-floyd-mayweather-muhammad-ali-undefeated-champion/

Please win Berto!!!