I learnt as a young worker the value of doing the things you hate until you become financially self sufficient or expert enough to dictate the things you prefer doing.
The time period between the two states should be as short as you can possibly make it. The reason is if everyday, you consistently do the things you dislike, you will need to deploy incredible amounts of emotional energy to sustain excellence. You will come home drained and somewhat frustrated. Even though you have a goal in mind, the longer it takes, you will become more despondent. After a while, the emotional energy you’re deploying will eat away at your health, peace and happiness.