I think it's an incredibly spoiled perspective that anything that becomes a chore is no longer fun or worth doing. Practicing piano is a chore. Repeating the same piece, the same finger movements for an hour or two isn't necessarily fun. But it is satisfying at the end of the day and it is fulfilling. Fun isn't necessarily the goal. I can spend hours banging my head against the wall while trying to build a piece of software. It can be tedious, frustrating, and tiring. It's rarely "fun". But in the end, it's satisfying and it's fulfilling and tomorrow I'll do it again because I want to.