I blame things like todomvc, which I think is great in spirit, but a huge menace in practice. It gives people false hope that framework x will solve all their ills. Any SPA that is more than trivial requires engineering skills. Additionally, it is likely that you'll be building said SPA with a team of developers who have varying skill levels. From my experience, a framework should provide a certain amount of level-setting (as opposed to something that is 100% custom) for new team members. However, there is nothing stopping people from putting data access logic in controllers or polluting the views with complex logic. Those sorts of mistakes can and will happen regardless of technology. The key is to pick the right technology for your team and the problem at hand and stick with it.