The marginal value of your time was not $0. You could have been doing something other than shopping with your time. That thing could have afforded you pleasure or had some other utility. The dollar value of that utility was not zero.
Even resting has some benefit to you. Unless your only alternative is some mildly unpleasant activity which doesn't allow you to rest, that time was not valueless.
Entertainment is useful. Excess entertainment is wasteful. Keyword being excess. I calculate the waste as: cost of the entertainment plus potential loss of income from missed opportunitys of work and training. Of course if your entertainment is bring some other tangible benefits, like exercise, then that needs to be factored in.
Even resting has some benefit to you. Unless your only alternative is some mildly unpleasant activity which doesn't allow you to rest, that time was not valueless.