> Honestly, for how many hours of the day are you actually productive?

Not very many. I would definitely love to leave at 5, and I know that this would make me more productive - in total! - not just per hour, but I don't want to deal with the fallout from it, since everyone else stays until after 7:30.

I tend to get in at 8-9, while others come in 9-10, but no one can tell how early I was in. As is, I'm already typically among the earliest leaving, and it already feels weird.