"We choose our actions, thoughts and feelings" Jonathan Lockwood Huie

I agree with this quotation entirely. People are the freest creatures on our planet. Nobody can make us do something, or think differently (is it clear? can I use "in another way" instead differently). Only we can do it and we must do it, we must choose our actions, thoughts and feelings.
Some people guess our feelings, depend on our actions and thoughts. But I have no doubt, that our feelings and emotions are more important and they form our reality. We were given a great variety of emotions. Some of them – like fear, anxiety and boredom - are negative, the other are positive. Feeling (can I use a word 'experiencing'? which of them does sound more naturally?) bad emotions are 'part and parcel' of lifes. (Can I use 'part and parcel' in this sentence? Can I use words 'fundamental, essential, integral, vital'? What's the difference between them?) We have to feel them every day, but we should concentrate only on positive ones. Our brain is very good at forgetting, bad experiences are quickly forgotten and quickly disappears. We just should let them go and keep in mind only good emotions.
In my opinion, the most significant positive emotion is happiness. And we should try to feel it every day. Moreover we should write down our happy moments, experienced during the day, in a diary. Write on daily basis at least one positive thing you've had over the past 24 hour will help you remember it. According to studies when we are happy, our brain works more effective, our thoughts are more bright, and we can work harder. (Is using 'bright' correct here?) So our feelings really can change our actions and thoughts.
In conclusion I'd like to share another quotation with you - “The foolish man seeks happiness in the distance, the wise grows it under his feet.” So do what you want, think positively and choose to be happy (Can I use 'being happy'?).

Could you correct my mistakes and answer my questions in the text? I will be grateful for your feedback about my essay.

Be careful of interpunction and using forms of many (is=are,life=lifes).

And yes, you can use other form to express youre ideas. Besides all of these mistakes your english is really good.