They're not telling you to base the relationship on some feelings brought on by sharing intense experiences together (which is what the movie says). They're telling you that by seeing how your SO behaves under the mentioned circumstances you'll get to see their true nature which can be eye opening for you.
This is the real advice. I knew a guy once who would get sauce on cheeks up to almost his ears...it was insane. I always wondered if there would be a woman out there for him. Probably not.
...based on intense experiences never work."
So which is true??