The reason why we should have and must think to control our emotions because this is a big factor that could affect our mindset. The majority of the traders had lost because they also lose their minds and uncontrollable emotions. But to be honest, it is really hard to do this, it takes time and commitment.
It takes time and focus, if you really wanted to succeed from this field taking baby step one at a time gives you more confidence in determining the possible next market movements.
Not easy but very possible as long as you have the right mindsets, planning ahead of time and making sure to adjust if there's a need doing so.
You can't control the market but you can deal with your emotions, practice and never to stop chasing the right system to use while you are working inside this business.