I spend more time during my lunch hour on TFP than at any other time during the work day. That being said, I do come and take peeks regularly during the day also. It's an obsession, what can I say?
I never let it get in the way of my work.
The thing is, I work hard in my job and I am very good at what I do. My boss respects me and recognizes my good work. He has once said to me, that as long as I get my job done well, how he wants it, I don't have to worry about occasionally needing to leave early for personal reasons - which I rarely, if ever, do. He has said to me, if you ever quit, I hope you will still collaborate with me on occasion. So I feel he is appreciative of me. I think the main thing is that you get your work done and well done. If you do that, I don't see why anyone has to get on your back for taking a break in a stressful day to relax a minute. It's as natural to me as checking my emails.
I get on well with all my co-workers and I know we all do other stuff online in the day apart from the work. I don't hold it against anyone as long as they are doing a good job.
I only wish I could have my friend's job - she works at a telecommunications company and the only requirement she has is that she get her work done and comes in at the same time every day. If her work for the day is done, she can leave halfway through the day and it's not even an issue. As long as she does a great job, mandatory work hours are not required. Which in a way, makes sense (depending on the job at hand). Say you have two employees - one works well and is fast at completing tasks. The other does so-so work and is far slower. Is it fair that they earn the same and have to work the same hours? Employee A will always be doing more work but getting paid the same as shitty employee B. If you trust your staff and give them a little power over their own work, they will be happier for it and more appreciative of you in the long-run.