I think that we are speaking slightly different languages here. I'm sure that your graduate work was pleasurable and maybe even pleasant, but I'm also quite sure that you weren't frolicking when you were working to finish your doctoral dissertation. I was using "fun" in the terms of frolic and frivolity while you seem to be using it in the terms of more generalized pleasurable activity. Sometimes the most rewarding things are hard work, but of course they should be pleasurable in the end.

Going back to my earlier comment, the person I was referring to had a great deal of short term fun (as in frolic and frivolity), but because of the long-term consequences he did not consider his two-year party profitable on balance. That's what I meant when I said that fun is not always profitable.