Enthusiasm is as elusive as love and just as infectious. But like love, enthusiasm can wane. And it’s also nearly as inexplicable (and just as much as a gift from G-d). Still and all, there’s one thing that ruins both: laziness. Take either for granted or slack off on them and they’re gone.
Now, as Ramchal sees it, we’re lazy as a result of warped expectations; as when we think we’re entitled to relax a lot, when we’re thrown off by inconvenience, and when all we want at bottom is to enjoy ourselves. But anyone who imagines he’s due all that and can still arrive at spiritual excellence as well is far off the mark.
Though deeply satisfying and as warming to the soul as song, prayer for example is a slow process. Grow impatient with it or expect it to ricochet against the walls on its own then leap upward and it will fall to the ground with a thud. Skim through a Torah work like a newspaper and it will nourish just as little; and hurry mitzvot and you’ll come away bony and listless there too.
For, serving G-d and growing in your being calls for determination, focus, and full effort. So “the sort of person who lives this way”, i.e., in hopes of unending relaxation, convenience, and pleasure, can’t help but be “burdened by the idea of Divine service” (when the truth of the matter is that nothing quiets the ravings of a restless soul, and nothing is more eternally expedient and delightful than true, slow Divine service, as the wise know so well).