My biggest mistake was uploading ASP code right onto a production server to fix an urgent bug when there were a few hundred people passing exams online. I didn'

My biggest mistake was uploading ASP code right onto a production server to fix an urgent bug when there were a few hundred people passing exams online. I didn't realised that changing pages would not bother but changing code in the APP_CODE section would make the website recompile the code behind and every data stored in cache or in viewstate would be invalid since the dll version had changed. Everybody online then hit a 500 error page when they tried to continue.