Fulfilling your responsibilities and enjoying life are diametrically opposed to one another

Everyone has responsibilities, as an individual, as a parent, as a son/daughter, as an employee, as a citizen, etc. Every group or category you belong to comes with a set of responsibilities that you should, if you have any morality or honor, fulfill. However the fulfilment of responsibilities often has little overlap with enjoying life, the activities necessary for the completion of your assigned tasks are rarely the same as those that bring great joy. Paying bills is a responsibility, planning funerals is a responsibility, adhering to your morals is a responsibility, none of these things are fun. Yet eschewing them in favor of fun activities erodes your value as a person.

Everyone wants to enjoy life, who would choose misery if provided an alternative? But in the pursuit of pleasure you reduce your own quality and likely the quality of life of the people around you, especially those you care about. If you pursue Hedonism, you might die happy, but as a person you have failed. If you pursue duty, you will die miserable and only a non-zero chance of being considered a success.

For those who would argue that moderation is key, consider that every action taken has the cost of every action not taken. It is not just the shirking of one responsibility in favor of a single pleasure, it is the shirking of all responsibilities and pleasures in favor of a single pleasure.