[govolckurself]

>I would rather solve fun problems than doing endless maintenance tasks.

Not everything in your career will be fun and exciting, and what you consider to be maintenance that you can ignore, some of us consider fundamentals that one ought to know to be considered a serious professional. Food for thought.

Edit: the real lesson is to avoid doing mission-critical, production work for customers without the requisite knowledge. This is hard to hear, but if people don't, they'll overestimate their abilities and get into trouble. It's fine to be junior, it's not fine to oversell your skills.