Inspiration will come along and tell you what to do. You can say yes or no — but don't even bother trying to haggle with it.
Suppose you are struck with a terrific idea for a song about rabbits entering a dance competition. You might be tempted to say, "That's great! Thanks for inspiring me! But I'm trying to write songs for my very serious death metal band, so let's just change 'dancing rabbits' to 'marauding werewolves.'"
You've tried this. You know it doesn't work. Inspiration's energy quickly evaporates if you try to redirect it to some other purpose. Inspiration doesn't care about your practical needs. It doesn't understand the importance of advancing your creative career -- even though your career success will actually make you better able to serve the whims of inspiration. Frankly, inspiration is selfish and short-sighted and not a team player!
But there's no point in complaining, and you're not going to be able to change the way inspiration works. So just take the few minutes to write down the idea for the dancing rabbit song, and then set it aside and get back to the very serious songwriting that you need to do.