How do you think investors should best add value to the founders?

What have you seen that the best investors do that is meaningful and helpful to the startups? I had a chance to attend an event with CEO of YC - Michael Seibel where I asked the above questions. This is his response about what he thinks are 3 criteria for a good investor. 1. Not remove the value out of the company. The #1 thing investors can do is not do harm, not giving you low evaluations, not try to run your company for you, not try to push you ideas because they saw something on clubhouse the other day. 2. Investors are the helpful conversation partners who you can talk to for an advice. 3. Good networks to connect you with people from who you can learn. Was wondering what is your experience and opinion about how should be the relationship between the founder and an investor?