Worked at a place that used on-disk XML as their database with multiple (10s of) writers. Started off fragile, ended up hideously complex and fragile. Unfortuna

Worked at a place that used on-disk XML as their database with multiple (10s of) writers. Started off fragile, ended up hideously complex and fragile. Unfortunately it was originally written by one of the powers that be and his word held sway over every technical decision, good or disastrous.