When they make movies, they always have a target audience. In general, when people watch movies, they imagine that it's them as the protagonist.
Porn is for guys who like jacking while pretending it's them. Action movies are for dudes who like to pretend they are alphas. Martial arts movies are for guys who imagine they're Bruce Lee.
Romantic comedies are for girls who like to imagine they're attractive enough and have enough self confidence to do whatever the "alpha girl" does in the movie.
Which means in real life, they don't. Nor would they likely want to. It's a brief, two hour fantasy. Most normal people know that.
I'm actually glad there are movies like "How To Lose A Guy In Ten Days."
It's a great way to "test" a girl in the first couple dates:
"I was flipping around on Netflix last night and I saw that 'how to lose a guy in ten days' movie. Pretty funny. You seen it? What'dya think?"
If you need some reassuring, there's ALWAYS tons of good, real life opinions on movies and their characters over at
IMDB.com, and thankfully, most girls and guys think characters like that are nutjobs.