Note

Spoiler alert:

A stricter adherence to standards comes at the cost of not allowing ambiguous behavior. Not allowing ambiguous behavior makes the developer's life more difficult. Making the developer's life more difficult ensures that the interpretation of the commands that the developer gives will not change later, breaking the application.

Just how lazy can you afford to be? I'm not sure how to measure this. PostgreSQL is available for no-cost future predictability, so I don't have to answer the question.

Sure, PostgreSQL also has some bugs listed. However, changes to the database core have a tendency to make the engine work like the documentation says it does, not like the documentation should have said. PostgreSQL developers don't have to say, "Oops, I didn't think of that," very often. When they do, PostgreSQL just becomes more standards compliant.