There are two big items missing from this list Empathy and understanding of users: If you don't know who your building for, and how they will use your app, you

There are two big items missing from this list Empathy and understanding of users: If you don't know who your building for, and how they will use your app, you have no way of knowing if your doing the right thing or wasting time. An understanding of business and accounting: Working for a startup and don't know what a cap table is. Does your businesses numbers make sense? Are your efforts going to capex and is it appropriate. Some of these things can be forgiven of a Jr. engineer. By the time your a lead, you should have a solid grasp on both of them.