It depends what you mean by "best". If you define a good job as one that will enable you to drive around in a BMW and have multiple holidays per year (after having pugged enough away to secure your financial freedom in retirement, of course) then no, running a market stall is definitely not the "best" business.
If you mean it might occupy some time in the last few years of your life, leaving you with less time to sit around doing nothing whilst still having the freedom to choose to not bother opening up shop when you don't feel like it (or maybe when you just have something better to do) then, I dunno, maybe it's a "good" job. Personally I don't fancy the idea of sitting around in the baking heat for 14 hours a day just to make a few hundred baht.
Of course it's mostly irrelevant - as running a market stall is a protected occupation that neither you or I can do, anyway.