Work for its own sake

I have written more than once about how in many cases Leibowitz takes a correct principle and takes it one step too far. The example I usually used was prayer. I completely agree that the motivation should be the obligation to pray. But from here to the claim that the intentions, desires, and content of prayer have no value, meaning that one could just as easily have recited the phone book, is a long way off.
I explained that indeed he is right that even in prayer, mitzvot require intention, and the intention is to fulfill an obligation. That's it. But above this basic level, there can be other levels that the more you add, the more value they will give: a desire to connect and stand before God (according to the Grach, this is part of the intention that hinders prayer). The intentions of the Ari. Aiming for some spiritual results, fulfilling physical desires, and the like. None of these can be the basic motivation in your prayer, but there is no reason to say that they are worthless and that there is no point in adding them. It is not for nothing that we revised the text of this prayer (praise, confession, and request), and not the phone book.