I remember many years ago I came upon a giant shell script doing some data processing (data not even that large, maybe few GBs) that took close to 25 mins (mainly due to unnecessary I/O due to tons of temp file creation) - written by "developers". I re-wrote it in Perl and it completed in less than a minute (and it wasn't even optimized because I was a non-CS newbie who was just learning Perl). I even setup a cronjob to compare the output from both and email to the concerned folks. It was never adopted because I was new and Perl was considered "too-risky".