A More Direct Approach To Joy
There are two ways to eliminate worry. One is to refuse to entertain such thoughts, just as we should reject depressing thoughts. Then, by avoiding worry and sadness, we can experience joy from doing mitzvos. There is, however, a more positive method, and one that is ultimately more effective, since it eliminates the very source of our worries. The best method is to strengthen our emuna in Hashem and our belief in Hashgacha Pratis. This is also a more direct approach to joy, since faith itself is a source of joy and vitality.
(Rabbi Yaakov Meir Shechter)