Misconceptions of Floyd Mayweather jr
1. He can't trade shots(watch him against Burton, Ndou, Oscar 12th round, Corley, Sosa...) Mayweather can stand in front of his opponent and trade shots though his opponent doesn't land all that much against him.
2. He doesn't have the power to hurt Hatton. Before he hurt his hand he was really wearing down Baldomir, and not hurting him, but definitely making Baldomir cautious. Mayweather rattled Oscar once or twice, especially when he landed those two right hands off the ropes in the 5th round, and with a body shot which leads me to the next thing.
3. Mayweather can't go to the body, Now I don't know if people have watched him fight, but maybe they should see him against Sharmba MItchell, Judah, Brusseles, Gatti, even Oscar. He has a terrific jab or cross to the body, and he has good hooks to the sides.
4. Mayweather can't handle a pressure fighter, first I am going to say Castillo didn't fight him like a pure pressure fighter, secondly many fighters who have tried to truly overwhelm MAyweather have been stopped from excessive counters(Chavez, Ndou, Gatti, Corrales, and I can't remember any others right now)

Misconceptions about Hatton
1. He needs to be the bigger man, I think he needs to be as small as he can so that he can keep up with Mayweather as best as possible.
2. He can take out MAyweather, there is no reason to believe he has what it takes to break Mayweather down, harder punchers have hit Mayweather cleanly to no avail... Mayweather takes a great body punch, and has a great chin.
3. He isn't fast enough, definitely he can't box with Mayweather, but he has the speed to stay on Mayweather all night if he is in the best shape of his life.
4. He throws a lot of punches, Hatton doesn't throw a whole punch of punches, but he picks his shots well, and when he isn't punching he is using his body to weigh on the other guy.
5. He won't be able to box, I agree he won't be able to stay in a distance fight with Mayweather, but I think he'll do alright avoiding some of Mayweather punches, and connecting with that right hand if he gets Mayweather in the right situation.