Thanks for the link Adelaide.
BTW, the chord pattern in this video is C G Am F (not Em)
And yes, some chord patterns are "standards" which sound good to our ears (at least ears used to listen to western music).
I used to play lots of jazz music, and two chord progressions are very well known by jazz musicians. That's what we call 2-5-1 and 6-2-5-1. I guess such patterns also exist for pop music or other genres.
For more info, you can google "2 5 1 chord progression" or "6 2 5 1 chord progression".