In living life, everyone will certainly do what makes them feel comfortable with what they do and does not make other people feel disturbed by what they do, each person has different ways of making themselves happy with what they do so that they are happy. You are right, everyone certainly wants their life to be better than yesterday and of course they do it in their own way.
I have to disagree with you. Even though it is ideally better to choose comfort in various situations, we cannot ultimately grow from it. If an individual chooses to just stay with where or what they are comfortable with then it will be harder for them to grow. Basically, we cannot grow by simply staying where we are and not exploring. The mindset you have stated can mostly only be applicable to those who are already in good standing in life, they can have the luxury to not submit themselves in hardships and stay in a comfortable state because they already have what they need and they are happy with that. Unfortunately, there are individuals who cannot do the same as comfort to them is not the same, comfort to them cannot be the same as it will mean settling for what they have and grown accustomed to and that cannot be enough as life demands more (more money, more effort, and more work) hence they first have to choose to go through difficult trials in order to find the same comfort they deemed fit to stay in.