I’ve also pondered this question in the past. It seems like you’re basically doing everything you’re supposed to be doing (going to Church, reading your scriptures, praying morning and night, etc…) and yet, you don’t feel that same burning of the bosom, or spiritual high that you’ve experienced before. I don’t think there is necessarily one universal answer for this question, but I will present one reason I think applies to many, if not most, in this situation.
Every week in Church, members of the Church make solemn covenants to take upon them the name of Christ, keep his commandments, and remember him. In accordance to those covenants, the faithful are promised to “always” have His Spirit to be with them. So… if we are promised we’ll always have the Spirit, and we’re doing what we can to keep our side of the covenant, why do we sometimes feel that we don’t have the Spirit with us?
I’m suggesting the answer is often that we are simply used to it. If we are really living the way we should be, and doing the things we’re supposed to, and have been for a descent amount of time, we are so accustomed to the companionship of the Spirit that it is not so striking or noticeable to us anymore. When I first joined the Church, I felt on fire every time I read the scriptures. Now, I occasionally feel a more powerful presence when I have one of those “Ah ha!” moments. Normally I just feel confident and peaceful. –What the scriptures refer to as the “rest of the Lord.”
A more poignant example comes from the experiences of Joseph Smith. When “The Vision” (D&C 76) was given to Brother Joseph and Sidney Rigdon, brother Rigdon was overcome with the Spirit and power of the manifestation. Brother Joseph smiled and said “Sidney is not used to it as I am” (Philo Dibble Recollections, Juvenile Instructor 27, 303-304). Brother Joseph was able to endure the vision calmly and collectedly, though obviously feeling the power of God.
What I tend to notice more distinctly is the absence of the spirit. A long time ago my best friend pointed out something in his family’s scripture study. Many think when we don’t feel the Spirit it is because He has left us. King Benjamin remarks that those who to contrary to the will of God withdraw themselves from the Spirit (Mosiah 2:36). At the beginning of my conversion (which all must go through) the strong presence of Spirit was striking and unusual whereas acting the way I had previously felt normal. Nine years later with a little bit of seasoning has altered things so that when I am in the wrong, the withdrawal or decreasing of the Spirit’s influence is more striking and unusual.
As we strive to live the right way, our natures change. We become “new creatures in Christ,” as Paul says (2 Cor 5:17-18). I pray that the long-suffering and loving-kindness of Heavenly Father, and the patience and refining nature of my wife will help stay me on the course.