Memories. Making a resume of some past brings out various memories. Once I have found out those good memories start to hurt me if the present has turned different. Like if the present is dull, empty, bitter. In general I somehow cannot look back on something that once was good with sweet remembrance. The lack feels too big, the missing too strong. Remembering some good past cannot make my reality better. Such remembrance makes the present looking even more sad, oh my.
Changes. I have always had troubles with those. Well, not if the situation changes for better. If the situation turns better, I can remember bad things that have passed with no harm, thus thinking over my development. But if things turn different, for worse, more bitter, then... I just cannot recall all the good that has passed without feeling that sting in my heart. In this case, the gap between what once was and now does not exist anymore, that kind of a gap and all those memories burning within it... well, that hurts as hell.