45 minutes in, and I noticed that I did not care about the serial killer. I did not care if he even existed or if it was [spoiler]. I did not care about the company's new marketing, I did not care about the three main characters.
Ten minutes later, and I noticed that I did not care how the movie would end. So I stopped watching.

I admit, in the beginning, I did laugh a few times -- and then the jokes either were of the same category or I did not even notice them.
There was no tension, the "scary" scenes never were exciting, let alone thrilling.
Scenes were often too slow, or not contributing to the story -- why should I be interested in how they market their shirts(? I think they make shirts.)? And I say this as someone who has a high tolerance for slow pacing, if it's done with purpose.
Come on, there are excellent Thai comedies, and great Thai thrillers! You know how to do it!

Two good aspects:
* Three woman in main roles.
* Very good acting, especially of the Boss.