If you follow that course, you'll never quit. Because nothing stops you figuring out what you really want to do with your life like being continually busy, chasing someone else's dream.

Time flies when you're busy.

Back when I was young and inexperienced I took some bad career advice and pushed myself through a degree in a medical profession, and then postgraduate training. With 20/20 hindsight I was utterly unsuited to the profession, temperamentally. But I was too busy to see that I was making myself unhappy (and doing a second-rate job in the process). It took 18 months of post-qualification work to get around to the idea that I ought to bail, write off the previous six years, and go back to square one, and another year to put the plan into effect. Why? Because I was busy. In the end I wasted seven years on a mistake that was clear by the end of my first year at university.

You only have one life. Use it wisely. If you find you're doing something that doesn't agree with you, think very hard before you push on indefinitely: nobody's going to give you those years back.

Sometimes the scarce resource is not money, but free time and mental availability. "Randomly walking around" could increase his chances of bumping into a hidden opportunity. I say go for it.

I'm one of those developers. And do you know why? Because it's not my business. I wanted to make some apps. I didn't put in a huge effort.

For the numbers to mean anything, you should filter out the 90% (or whatever) of apps that aren't intended to be part of a serious, profitable business.