I’ve a new frequent mistake, but am notified immediately when I do it. We use the # () and #Get () custom functions pretty much all the time to pass multiple parameter to scripts and subscripts. We also use the ~ key for calculation variables in the likes of Let () and While () calculations.
Within a script, we usually don’t convert the hashed parameter variables into visible local parameters but use the #Get ( params ; "variableName" ) throughout. Constantly I am entering the ~ rather than the for my local variable, ~params rather than $params which of course the calculation engine picks up on every time. Only recently became aware that I was doing this. Doh!