Ask HN: Have you ever chosen Postgres over Mongo and regretted it?
My example is a bit dated, but may be illustrative:  I chose PostgreSQL over MongoDB for a MEAN webapp (making it PEAN?) project started in 2013 and regretted it.  I was constantly struggling with the poor support for SQL in Node at the time and spent way too much time fixing bugs or adding workarounds for deficiencies in the SQL abstraction libraries and ORMs, or writing bespoke SQL and object mapping.  After switching to MongoDB, I spent significantly less time on storage issues and development speed increased noticeably.Later we did run into several issues caused by MongoDB which could have been avoided by using SQL (mostly related to consistency, constraint enforcement, and problems with MongoDB's aggregation capabilities).  MongoDB got us to market faster, but had higher costs in the long-term.I think there are two lessons that I'd take away:  1) There are costs to choosing a less popular technology combination, even if the individual technologies might be better (for your particular needs) in isolation.  2) Sometimes it's better to choose the more costly technology in the long-run to avoid costs early (i.e. incurring some technical debt can be the right choice).  MongoDB vs SQL for us was an example of both of these.Note:  I assume SQL libraries in Node have matured significantly since 2013, so I wouldn't necessarily recommend MongoDB over SQL for new projects starting today.