Writing is many things
Writing can be a career, or several: novelist, journalist, biographer or any of several kinds of non-fiction writer. These are far from mutually exclusive. Alternatively, you can write for fun, therapy or compulsion, and these too are far from mutually exclusive. You can write in solitude or as a team. If it is a career, or if you would like it to be but need something more predictable as a source of income, you can combine writing with a day job (or you could write in the day and work nightshifts). Whatever suits you.
Writing is flexible
As I said above, you can combine writing with another occupation. On the other hand, if it is your main occupation, you can write whenever and wherever you want. Early bird? Fine, kick off the day with a spell at your wordprocessor. Night owl? Fine! Start writing after the late news. Anything in between is all right too. I write mainly in the afternoon, but what works for you?
Write at your desk, on your lap on the sofa, on a park bench, on the train or bus, in a (parked!) car or wherever you like. If you use a dictaphone you can write as you walk, run or cycle. I work mainly at a desk but think things through when out walking.
Writing gives you scope
You can create characters based on real people you know or have known, or you can invent them. Many of us put ourselves into our main characters, but we tend to improve them. My heroes are younger, stronger, cleverer and braver than me. I can do things through them that I can’t do in real life and I can let them do things that would get me into a lot of trouble. Actually, they usually get into a lot of trouble, but I can get them out of it.
You can set your work anywhere, whether in places you know or used to know, or in places you’d like to go. Perhaps in places you are determined to keep away from. Set your work in the present or any period in the past, or you can invent a future. Use your memory, your research or your imagination.
Writing can improve the World
You can influence the world through your writing, by showing up things that are wrong or by suggesting how better they could be. In another sense, you can improve the world by making things turn out the way you want leading to justice, retribution, reconciliation, or repentance. In a whodunit the villain usually gets just deserts and there is often some discussion about justice in a wider sense, as in DOWN for example.
Writing can be fun
You can insert humour into your work: funny stories, funny characters, witty lines, playing with words. Your world can be funnier than the real one or it can reflect the humour that is there, alongside the sadness and injustice. Cheer yourself up, and others. I have said why humour is important.