Can It Really Be THAT Easy To Guess Someone's Password?

I was watching this movie on tv last night and to make a long story short the main character had to get into another person's computer so that he could stop a catastrophe from happening. Of course the clock was ticking and he had to get into the computer right away! But the computer had to have the password / code typed in to gain access to the computer and of course the main character didn't know what it was so he had to guess.

He tried a couple of times but it didn't work. Then he thought about what the person loves and then typed that in - that didn't work. Then he typed in what the person hated - and that worked!

Even though I kind of enjoyed watching the movie I thought to myself that it couldn't possibly be THAT easy to guess somebody's password!