Most everything important in life cannot be imagined. I cannot imagine:
• life without chocolate and cherry kool-aid;
• lighting something on fire and then putting it into your mouth; (I think they call that “smoking”)
• anything more comforting than a warm grilled cheese sandwich on a cold day;
• being married to anyone other than my wife, and having a more beautiful context for living than the one she has created for me;
• my life without a testimony of the perfect gospel of Jesus Christ as restored through the Prophet Joseph Smith;
• any book of scripture more true and relevant to my personal spiritual needs than the Book of Mormon;
• death without something after it;
• being happy without my family, my religious beliefs, and my God;
• the depth of sins and sorrows my Savior bore for me.
Perhaps my imagination about these elements fails me because they are so real. They are woven into my character. I'm ok with that. What's wrong with your imagination?