My biggest problem with databases is that they are very hard to evolve. They accumulate a history of decisions and are in a suboptimal state. Legacy is widespread in enterprises. Oracle is still milking $ 50B+ annually, and the databases are the primary driver of why you need Oracle and why they can upsell you other products after a compliance audit.

The schema changes are hard (e.g. try to normalize/denormalize data), production is the only environment when things go wrong, in-place changes with untested revert options are default, etc.