Using Oracle ADF along with ADF Faces to build a simple learning management system. No JavaScript, no external stylesheets, all inline styles, no client side validation, doing form submit for every field's onblur event triggering a server-side validation, creating a VO for every damn page requiring data, creating an EO for every DB table or view, adding big-ass custom queries for most EOs to join on multiple tables, frequent N+1 queries, etc.,

Idont remember the rest of the problems