So when we started this project like 4 years ago... new to the framework, kickstarting lot's of forms with file uploads. Everything seemed to work fine, uploads and downloads worked..
First version of the project got deployed to prod and for weeks or so users have been registering and submitting stuff...

Only problem was: most files were overridden by consecutive uploads as our central upload lib stored files with the same name on disk (normally the ID of the db row was injected but most files were saved before the db row was - resulting in 0 IDs...)
Yeah so... that hurt :(