Guilty, but as with anything there is a right time to use it and a time to most definitely avoid it. If you are working with others in particular there is very little room to wing it.

Experienced devs can do so in a first pass to flesh out an idea before letting the team get involved, but thereafter the design immediately becomes rigid. Inexperienced devs can wing it to learn in an exploratory way, but their work is unlikely to be re-purposable.