It's all about perception, sadly. Plenty of people who will judge you and gossip about you for what they deem to be slacking. (Often while they're having a "quick" cigarette break, just for the irony).

It's not ideal, but it's human nature, and I don't think any company, no matter how good their culture, can remove it.

I worked in an open bureau back in 2001. One guy would watch a funny video and the whole bureau would go to his computer to watch it. I found that very annoying, I'm here to work and solve (hard) problems, not watch videos. Because I was unemployed for a long time before that and was happy to work and do something productive. Instead..they watch videos. I also can't stand inner company politics. If I never have to talk to my colleagues it's the best. When I joined that company there was one guy who said, "we're all freaks here, what kind of freak are you". I never saw myself as a freak. The company imploded in the new economy bubble because management thought that spending 250k on Reamon (the singer) was a good investment. Then they didn't have enough money to pay their developers that were by 9/10 from Russia or Romania, imported. We sued and never saw our money. The product was sold to T-Online (Deutsche Telekom) as the TOM (T-Online Messenger) and the CEO fled to Switzerland with the money he made from the sale. We didn't see 1 cent. What's also interesting, on paper the chiefs like the CTO and the head recruiter earned 20fold of what the code monkeys earned. It was also a family business and they called themself a company that was noted on the stock exchange but in reality wasn't registered there. The brother of a, at that time prominent TV moderator was an investor in that company.