Python just cost me half an hour. The problem: a comma instead of a period.
Runtime and two linters said everything was fine. Except it wasn't.
Soapbox: Programming languages should not have syntaxes where something like this is possible. Compact syntax is all nice and dandy, but there needs to be enough redundancy that things like this are easily caught. Otherwise we'd all still write software in hex.
@J12t
yea, there's probably an argument that the comma is an overpowered part of the syntax given how small and similar to a period it is.
It's probably the buckling point for all the strains that the whitespace-as-syntax design creates.