Having worked a lot with neo4j, a graph DB, over the past two years, I must say I'm surprised how rigid and inexpressive SQL is by comparison. We started our project with a SQL database, but some queries would be 10 or more lines with multiple joins. Very hard to read. Once we switched to neo4j, the same query was a single, easily readable line.

SQL is very well-established, but it's also old, and it shows its age. It's kinda weird how easily we jump from one programming language to another, and yet we can't seem to move on from our main relational query language.