Headscratchers / Shallow Hal

• The hypnosis didn't just make Hal appreciate inner beauty, it gave him psychic powers. He can determine a person's personality from across the room, instantly, without even speaking to them.
• Why does Hal refuse to believe Mauricio's persistent claims that Rosemary isn't nearly as attractive as Hal perceives her? Because Hal has become convinced through Mauricio's constant rejection and avoidance of perfectly lovely would-be paramours that Mauricio either has ridiculously high standards and/or is just outright afraid of women, or at least relationships with them. So Hal would naturally dismiss Mauricio's warnings, even though they come from his best friend.
• Some people find "ugly" (at least in Hal’s point of view) rather attractive. The reason that Hal sees people he would find unattractive as thin, gorgeous ladies is because that is Hal's type at the beginning. If someone finds larger or untraditionally pretty people attractive, they would see skinny girls as what they think is attractive.