Did you ever wonder why do you do certain things? Why do you accept them? Why dont you step out of the crowd? Why dont you just leave? Why dont you just do what the rest do? Why dont you just get over certain things? Why do you get lost in details, unsignificant people, simple rocks that will be left behind in your long trip?
I guess the answer would be that we will remember those rocks because we stepped on them and they hurt. And as the wounds may heal, our memories wont ever recover.