They are working on installing a new data center in town, a bunch of the townsfolk are going all NIMBY to try and stop it, I'm trying to understand why?

I've toured a datacenter in California and it was a pretty straightforward thing: bunch of computers, cables air conditioning, a couple of people working there. I know there are some differences depending on the type of datacenter, but what am I missing? Why are all of these people up in arms over some rack servers?