Deviation or exploration

I know I should focus on preparing my final defense and publishing my dissertation. But I am already looking for other things that might not be directly related to those tasks but rather out of my curiosity or (I hate to say this) instant interests. Whenever I encounter new concepts or ideas, I couldn't put the new things aside. They keep bothering me and tend to take the priority, which in may times turns out to be a bad practice. I should try harder to change my bad habit so that I can balance things I am juggling with and start something new only after more important tasks are done or almost finished.