ALL of them. Cut all the excuses.
Legitimate reasons for not writing do come up in life, be it illness, family, work or other. A lack of inspiration is not a reason, it’s an excuse. A lack of time? Nope. Place? No way. Audience considerations? Characters?
You have time to write. You may not always have enough time handy, but you can make sacrifices. You don’t need to watch that episode of Latest Reality TV show, though it’s okay to keep it as a reward for when you write. You don’t need to finish New Game the week it comes out, or read that book today, or stay out for all hours. There is always time for something, even if you just get 100 words in, or hold off on the short time-wasters that do add up, and just sprint through for 5-10 minutes. You don’t need to churn out 5000 words a day, but you can do some. Steal every minute you can. You choose when you write.
You can do it anywhere. Find a cafe, or a library, or a spot in the park. Find a space at home. If your only privacy is in bed, write in bed. You choose where you write.
You can write the story you want to. Are vampires overdone? Maybe. Do you have a vampire story you’ve been sitting on for years and really want to do because you think you can do justice to it? Then the only thing stopping you from writing it is you. It doesn’t matter what the big trend currently is, or what you think it will be next. All that matters is what story is important to you? You choose what you write.
You are the one that decides who your characters are, and what they do. Society and the publishing industry might conspire with regard to the stories of what is popular or published, but it’s you that makes the choice. If as a writer, you lament the lack of strong role characters for a particular trait or demographic, that’s on you. If you want society to be different, you have to be different. You choose who you write.
Computer playing up? There’s pen and paper. You don’t need a fancy word processor or a pretty notebook, though naturally these are nice to have. If you’re on the go, you could use your phone or tablet or record your voice, and email it to yourself to transcribe later. You choose how you write.
The only thing we don’t get a choice on, is why we write. The reason is there, whatever each of ours might be, and we just do.