It seems to me that one of the most common words in our American-English language is "should". We're taught as children what we should and shouldn't do to be good, or to avoid being bad. Life is set up from the start as a game of skill and luck to win good points and avoid bad points. We carry this training with us and evaluate all possible choices according to whether we should or shouldn't, usually unconscious of the subtle subtext of judgment—"If I do it, will I be good?", "If I don't, will I be bad??".
Whenever I think or hear the word "should", my immediate response is "Says who?". We have internalized the adult voices from our childhood and we whip them out regularly to flagellate ourselves and judge our every choice and action. My response is that of a typical rebellious child who doesn't want to do something just 'cause Mom says. As adults, we have finally gained the right and privilege to make our own choices based on what we deem best for us in light of the situation and the well-being of all involved. When we unconsciously continue to wag a judgmental finger in our own direction and guilt ourselves into doing or not doing something, we are bowing down to the "should" and surrendering the power of our own intellect and free will.
The word "should" can be ejected and replaced with healthier ways of thinking. Replacing "should" with "could" indicates that you have a choice in how you spend your time and energy and that, as an adult, making your own choice is perfectly acceptable. For example, "I should eat something healthy" versus "I could eat something healthy, if I want to". Taking the thought further, "should" can be expanded to "I want to do this because..." which puts the power of decision in your hands and allows you to clarify your own reasons for making your own choice. Furthermore, "should" can also be transformed into "It would be healthy for me to do this because..." which helps you identify real reasons for making that choice, rather than doing it because some authority or entity decided you have to.
A big piece of becoming an adult is making our own choices and dealing with the results those choices produce. We no longer have to do things because someone says we should. WE get to decide what we choose, why we choose it, and all the whens, hows, and wheres associated with the choice. This is an important aspect of appreciating freedom, using it wisely, and reveling in the joy of adulthood.