Sometimes I do actually write.
  1. It's too early.
    I got up early especially to write but it's just too early. I can barely see let alone write. Can't find my glasses. I'm going back to sleep. I'll write tomorrow morning.
  2. I'm too tired after my day at work.
    I've used up all my mental energy at my day job and now I'm too tired.
  3. I would write but in in the middle of binge watching ______ TV series and I really should finish it.
    If I don't then it's all I'll be able to think about when I'm trying to write. Let me just get this very important task out of the way first.
  4. I'll check my emails first, then I'll write.
    We all know there'll be no writing now.
  5. I'm too busy reading random Wikipedia articles to write.
    Suggested by @minhal