Photo Credit: Andy Mangold (Creative Commons)
In Job 29 Job reminisces about days long past. This is something people tend to do when life gets tough, and there is no change in sight. However, Job was very close to bragging, as he recounted his good deeds and past prosperity. It is better to remember our past blessings from God than our past accomplishments.
The other problem I see with dwelling on the past when things are bad is that we minimize the challenges that were encountered in the past and only remember the good which is not a clear picture of the past. It's what the Israelites did in the wilderness when things got hard. They wanted to go back to Egypt because they remembered the good, but they failed to recall the oppression of their slavery. If we're always looking back, we cannot move forward into the future God has prepared for us.