Take the Israelites for example when they left Egypt they had seen more visual miracles than most people. One would think that seeing these miracles would allow them to trust God unconditionally no matter what. They left Egypt with the promise of being lead to a promise land of milk and honey. But once they left Egypt they started to complain.
Some of their complaints were that they did not have the food that they wanted even though God had provided manna (or bread for them to eat) they wanted meat instead. Then God provided meat for them (quail) and it was too much of it and they complained about that. They complained about walking, how long the trip was taking, and felt that it was better in Egypt. Even though they saw God's miracles and even though they knew that God was leading them to a place to milk and honey. They began to doubt God and wanted to go back to a place in which they were slaves.
It would seem as though they forgot their maltreatment in Egypt, forgot the fact that they were "God's chosen people" and were treated as slaves, and only had selective memory. Remembering the minimal good things and not the many bad things they had to endure there. And so they rather go back into the past to a place of bondage as oppose to moving forward to their future.
The kicker is that they needed to go through the desert in order to get to the land of milk and honey. This was a trip that was suppose to take two weeks that ended up taking them 40 years because of their constant complaining, unbelief, and inability to get over the past of where they came from.
How many times do you wish that you had stayed in a relationship knowing very well when you were in that relationship you were miserable? But now since you are single you prefer any relationship, even though it may be terrible, over being alone.
But like the Israelites it is going to be hard to get to that land if I am always looking back on the past idolizing a situation that was not so great. I was only looking at the money aspect of it and not the fact that I hated it, the people had a lot of drama, it was highly stressful, and it was not what God was calling me to do.
I am sure that this is a lot of people, and this yearning for a past that you cannot change or go back to is often the same thing that is keeping us from going into your future. The inability to get over the past can lead us in one or two directions. It can lead us to miss out on our future all together or delay of a blessing.
If we trust God we have to trust that He sees all and knows all. We have to trust the direction that He is leading us in is the right direction even though we may not see it or understand it. Most importantly we have to understand that sometimes we may have to go through the wilderness in order to get to our blessing. And if we understated and accept all of these things, then we cannot stay in a past that was never intended to be.
If something in your past was meant to be, then it would. There would be nothing to stop something that was meant to be, that is the basic definition of "meant to be." But since it isn't, there has to be a reason for that. Instead of wallowing in it, accept it, and move on. Trust that God knows what He is doing, and do not allow the inability to get over the past affect your future.