Eight years ago my daughter asked me to make her a mediation bench that would break down so it could be packed in a suitcase when she traveled. Pretty soon some of her friends asked to make some for them. Then a friend of my wife's..... I may not be the brightest but I was beginning to see a trend. At the same time I was wanting to buy a new jointer/planer combo unit but I couldn't really justify the expense. It was a want not a need. So I decided to give it a run on etsy and it was successful enough for me to get the jointer/planer combo unit. But it also consumed most of my shop time that it really did become like a job so I stopped making them. But I learned a lot about streamlining repetitive tasks (jigs) and the value of fast drying finishes.
So if you've ever had something that a number of friends have wanted you to build, maybe that's your ticket.