Avoiding "you" and "I" can at times provide greater freedom to express what you want to say. For example, attributing your own thoughts, feelings, frustrations & anger, or perhaps even self criticisms to a fictional or representative character "him" or "he" can free you to say what needs to be said, free you from the restraints of the subjective to the clarity of the objective. In that way you can also turn a pitiful woe is me testimonial or expression of derision into a tale of a sympathetic or loathsome character. An age old tactic is the utilization of a fictional name other than the person to whom in real life you are actually referring. Or simply say "he" rather than "you". On the other hand, "you" might be the perfect word.
There are no rules, keeping in mind most people shy away from overt self pity and/or meanness. The path you choose is determined at least in part by your intended audience, of course. Some people write for themselves, which is fine.