We were hiring developers for a large, complicated application. I happened to mention to one of the more promising candidates that the application was fairly write-heavy and we might experience some performance concerns later. This developer, with years of experience and skills across multiple technologies that might have been of use to us, replied “you’re going to either need to shard your database or switch to NoSQL.”

That was enough to guarantee they didn’t get the job.

Before relational databases, all databases were NoSQL. That’s why we have relational databases.

Great read on why database design is so important