There are people who make a hobby of telling others what they can do and what they can't do. I've learnt to not listen to those people.

If someone wants to start a business but they don't have an idea that they are specifically passionate about, then it may not be the right time for them to start it. Instead, they should work with someone else who is doing something they care about in the meantime until an idea comes up.

People tell you keep your job, start the company on the side. If I'm doing it on the side, then probably one of the reasons it fails is because I didn't dedicate enough time to it.