Category A is energizers. They're people you trust, admire and respect; they give you good advice and help you grow.
Category B is people you like well enough. They are reasonable to work with.
Category C is battery drainers. They're users, underperformers or people you believe, for whatever reason, are your enemies.
Now think about the time and energy you spend on people in each category, including the time you spend thinking and talking (complaining!) about them. The Category A people are the ones you should be reaching out to: if you go to lunch, they are the ones you invite. Category B people may have roles that make them important to Me, Inc., so stay in contact with them. But limit the time you spend on Category C people as much as you can.