Following people doesn't negatively effect your HubScore unless you write low-quality Hubs, or no Hubs at all. Following people and receiving followers actually increases your HubScore over time. Don't abuse it though! Following too many (as many as you can, all the time) and not leaving insightful comments or reading others Hubs will bring down your score somewhat. I will share a link with you to an article in the HubPages Learning Center that explains both the HubScore and the HubberScore; yes, there are 2 different scores! https://hubpageshelp.com/features/Learning-Center-...
I hope that this answers your question and thanks for asking! You noticed that I follow a lot of people which is true. I am a HubGreeter (http://hubpages.com/learningcenter/hubgreeters) and I introduce people to the community and try to point them in the right direction as to getting started on HubPages, the ad programs, etc.
I also follow people when I am interested in their articles while browsing the HubFeed and the HubHopper, and I usually leave them a comment on their Hub. Leaving an author Fan Mail is another great way to show your appreciation for them, and you can tell them why you like them/follow them through the Fan Mail.
Good luck to you and contact me if you have any more questions!