> Probably 80% of notable performance problems I’ve seen in the kinds of systems that things like Django and Ruby get used for have been terrible queries or pat

> Probably 80% of notable performance problems I’ve seen in the kinds of systems that things like Django and Ruby get used for have been terrible queries or patterns of use for databases (I’ve seen 1,000x or worse costs for this versus something more-correct) ActiveRecord pattern saves you a few lines of code now, and explodes your foot off later.