We wrote a backend service at Lyft in Python and at some point needed to do some string interpolation for experimentation. In a rush someone implemented this in

We wrote a backend service at Lyft in Python and at some point needed to do some string interpolation for experimentation. In a rush someone implemented this in YAML (no new deps needed). This ended up being the bane of the teams existence. Almost impossible to test if something was going to break in runtime, could only verify it was valid yaml but many other things were infeasible, super hard to debug - it soured me on YAML for years.