Many people are concerned about how to control their emotions.

That's a fundamentally wrong question. The point is not to control emotions, including so-called "negative" emotions, but to first understand why they actually arise - what in your mindset compels you to perceive one or another phenomenon of reality as negative. That's the main thing. As for trying to control emotions without knowing their roots, it's like chasing your own shadow.The main task is to get out of the vicious circle: negative emotion — negative attitude — an even stronger negative experience. But to hope that you can do it all at once means to inflict fail, since your attitude and manner of reacting to external events has been formed over the years.