At my first job, we had a free soft drink machine (one of our main clients was Coca Cola and I think they arranged and stocked it for us). This seemed like heaven to me, and so I remember indulging in three cans a day for at least two weeks. After that, I dropped down to only one can a day and didn't really think about it again.
Another time, I did a project at a cigarette manufacturing company, and each month you could take all the cigarettes you wanted to, as long as it was for your own personal usage. I didn't even smoke, but that didn't stop me from trying.
Free lunch and unlimited soft drinks every day :)
Love it!