Do you have to do it? For me, I have to. The reason:

This is a Capitalism society. If I don't participate in the capital system, I lost from beginning.

If I have to do it, I focus on how to do it correctly, not to excuses why I cannot do it right.

For me, this is one way to live in this society. Not the only way I live. I have and will have a engineering job. I love it, just like I like trading.

Of course not everybody want to do it or can do it.

For your reasons:
1. You have freedom to buy, sell, or wait. That's much much more freedom than you could have in any other society function.
2. Your buying/selling/waiting create the market, with millions other people.
3. Your trading allocates resources. You are doing "God's job".
4. You could have friendship here (DQ) or outside stock market, just like many other stay-at-home jobs. If you are a friendly people, you will have friends, one way or another.