Rabbi Mordechai Machlis gave an interesting teaching last Shabbat (Erev Tu be'Shevat):
Actually there is a positive commandment to enjoy G - d's creation ! Tasting His fruit, for instance. As we also celebrate on Tu be'Shevat.
What does it mean "enjoying G - d's creation ?"
Of course, each of us has a different kind of understanding of what exactly "pleasure" is. G - d, however, created this world with all kinds of beauties: nature, food, music, etc. Our Mitzvah is to enjoy all this. Otherwise G - d could have created an empty world without any trees, tasty food or drinks. Then we were only doing our Mitzvot and Tikunim (soul rectifications) and that's it. Instead, G - d created a beautiful world and we must enjoy it and thank Him for the creation (as we do with the blessings).
"Pleasure" always means "pleasure within the halachic frame". Enjoying His food doesn't mean that a Jew can run around and eat what he likes. Many people misunderstand the concept but don't realize how much we can enjoy even if we stick to Halacha. Enjoyment also means Judaism and Mitzvot.
Further, "Enjoyment" means that we have to open up and look around in the world. See all the "pleasures" G - d has created for us. Some people like traveling, others love eating. What we should not to is closing ourselves up in our little community and keep separated from anything outside. Should, for instance, a strict chassidic group shut itself into it's backyard in order not to let any "impurity" in ?
Can this "keeping too separate" still be an enjoyment of life ?