Our posterity can learn a lot about us by what we record.
Journals are great to pass on your thoughts, life challenges, your testimony, etc to your posterity. In the early 1980s, we were encouraged as church members to begin writing in our journals. For me, it was much less frustrating to organize my thoughts by using a digital medium, like a computer. However, it is also fun to see what your ancestors handwriting was like back many years ago. Journals can now be scanned easily and then SHARED with other family members. Journals can also harbor short stories of events that could be typed into FamilySearch stories and then shared with others.
Scrapbooks are also a fun way of expressing your life through a combination of photos and annotations. Don't forget to save a digitized or preserved copy as well. There is nothing like a flood, fire, or theft that wipes out a lot of your life's memories.