I agree, and yet I think it's important not to focus too much on pleasure. Not just for the sake of productivity, but for the sake of one's own happiness. Caring about more than pleasure makes it easier to be happy. The Buddha had a lot to say about that.

Then again maybe that boils down to a mere alternate definition of pleasure. Newcomers to exercise find it painful, and that feeling never really goes away, but some learn to enjoy it.