Being a writer can make you feel selfish. The craft requires considerable time, concentration, and for some, a particular writing environment. Taking some time for you is not selfish. In fact, if you are like most writers, it may be necessary to maintain healthy relationships.
Without taking time to write, writers often become:
Just to name the main ones.
Why? That is the question most non-writing people ask. They do not understand why stopping in the middle of a scene to answer a question about dinner can set you off in a mood. Give them this information.
Why, you ask? The answer is as complex as it is simple: because the writing is still happening in their head. The script, the scene, the characters are all still trying to push their way out and onto a page somewhere and that writer you are spending time with needs to get them out in order to spend quality and focused time with you.
Writers, take 10 minutes, take 2 hours. Take that time to write. Sure, your characters, plot twists, etc. may still try to invade your mind, but it won't be as much if you can at least take some time to get part of it out in a notebook, as an email or text, possibly a voice note, or ideally typed up in a draft. You do have to make good on the quality time with those giving you the undisturbed time to write. You want to make time for those people because time is the most precious gift someone can give a writer because not all writers are writing for publication and income. Some write for themselves.
If you are starting a writing practice, grab a journal or open a document and take 10 minutes to write. Then do at least 10 minutes every day. It might end up being two lines of dialogue. It may be a note. Every word counts.