Emotions come spontaneusly , noone can guarantee to control over it even you have planned it all since long time ago.
You should get used to have a good emotion control in your daily life , otherwise any goal will get broke with your uncontrollable emotion.
I agree with your opinion, everything that we do without stable emotions, everything will just be in vain, it is very difficult to control emotions, but if we run it with the heart, surely we can control our emotions.
You stake money there in hope to get profit and controlling emotion never be easy.
You know why it is because you never did it since first time , so simply you need to train about it more often , gor example keep thinking to play safe to get a little profit but steady.