Working at a small university changed my code because the university hosted its own sites.
I knew just enough about the hardware setup to see where problems might occur for me and started adding 'just-in-case' code.
Then I read a ColdFusion book that suggested using a simple database query wrapped in a cftry/cfcatch tag just to see if the database connection was up and running.
I laughed because I thought I invented that. My code used a cfmail tag to emailed me so I could go and nag the database guys.