I've recently learned to love puzzles! I helped a woman finish one recently and it was fun to sit back and admire how well all the pieces fit together. I looked at all the little pieces that had given me trouble and chuckled to myself. After it was all done it made sense, yet some of those pieces were so challenging and didn't seem to fit anywhere!
We each can understand once we get to algebra why the basic 2+2 was an important thing to learn, and that concept applies with every lesson we learn. We get through trials and, later in life, realize just how important that particular challenge we had years ago prepared us for where we're at.
In essence we put together those puzzle pieces. But it's hard to see the full perspective with just one little piece. The Lord is able to see the whole image, put together, and knows what pieces to hand us.
We too can gain a glimpse of where and how the puzzle fits together as we turn to the scriptures. The Lord has given us the tools. He's given us the image on the box to look at for guidance. We can also pray and ask for the added guidance. Then someday we'll be able to lean back and say, "aw, so that's how that piece fits in..."