Eh, there is a lot to screw up too, like determining whether you have the remaining bandwidth /amperage in your panel to spare, which gauge wire to use, whether to use romex , metal clad or metal conduit, if conduit which size to use, which ampacity chart to use (60C, 75C or 90C), GFCI or not, etc etc. You can run some wires and probably end up with something that works, or maybe you have something that runs hot becuase you didn't use the correct wire, or maybe you were pretty well maxed out on your panel and your main breaker is tripping. And there are all kinds of areas in between, maybe it works well for several years but you mated copper to aluminum incorrectly and over time the connection fails. For something like this, I don't think it's reasonable to discourage someone from using a professional. If you know what you're doing, that's great, but there is value in hiring a pro for even what should be a simple job.