Maybe I'm just extremely lucky, but I think in 20 years of working at multiple companies (as an IC), I've never really even had contact with HR besides my first and last days. I don't think I could even name a single HR person I've ever met. They tend to be there to hand me the benefits literature, then at the end I give my badge back to them, and that's it. What on earth is happening in companies where HR is part of the daily life of a standard "3rd engineer from the left" employee?
I was a manager, so I had plenty of interaction with HR.
For the most part, they weren't actually bad people, but their job was to be fairly two-faced. I think it caused a lot of issues. HR had the highest turnover in the company.
The last time I had dealings with HR, it was because I had reported that my boss did something illegal, and I told the head of the company.
They tell me to deal with HR, and HR tells me that I should have talked to my boss first.
In short, the heads of the company didn't want to hear about the illegal stuff, and HR was their shield for it.
My boss actually told me, "I could get fired for what you said." It wasn't what he did that was the problem in his mind, but that I told people about it.
I didn't last much longer at the company. They didn't fire me, but they also stopped giving me raises. When I asked for one, I was asked if I could "wait a year". I found a new job for a 40% raise 6 months later.