Your PKM system shouldn't be frictionless
I think some of the PKM power users who try to make their systems as frictionless as possible fail to understand that a tool is actually better when you work with its limitations rather than against them. When you can't fully automate the process of capturing and storing knowledge, it forces you to actively consider what you're trying to accomplish. You have to think about why you want to save a given piece of information at all. Knowing you're about to face a little bit of inconvenience might lead you to avoid saving an article or quote to which you would never return. After all, a personal knowledge management system is only as good as the knowledge it contains, and thus the first step to building a good system is being more thoughtful about what kinds of knowledge you choose to retain.