Most of what I mean is places where Feldera/Calcite has slightly different syntax from Postgres for things. For example, Postgres syntax for cast to bigint is `some_expresion::bigint` although Postgres also supports ANSI SQL `CAST(some_expression AS bigint)`, most examples I find in the wild and in my own Postgres SQL use the Postgres special syntax. JSON syntax also differs; Feldera uses its own pretty elegant `VARIANT` type and `some_expression[key_expression]` to access properties, where Postgres calls this `json` or `jsonb`, and uses `some_expression->key_expression` to access properties. In those cases it's not like Feldera is wrong or lacks some support, but it's a bit harder to work with for me because I'm so used to Postgres syntax and I need to do some regex replace whenever I bring a query from Postgres over to Feldera.
Definitely not a deal-breaker, I am a Feldera enjoyer, but it does add some friction.