Memories can be capricious. The strongest memories are those that have a strong emotional connect.
One may remember the exhaustion & exhilaration from a physically or technically challenging surgery for days or weeks but the feeling will gradually fade & eventually be relegated to the archives of memory as we move along with our professional and personal lives. We are only reminded of them when we meet those patients again.
The ones that we never really forget, those that keep coming up to the surface time and again are the moments in which we felt absolutely despondent and emotionally drained as we helplessly watched the life of a patient slip away as if it were sand between the fingers, even as we were desperately trying to save them.
All such experiences leave a scar, some more deep than the others. Some may act as a motivation to learn your lesson, pick and dust yourself off, and move forward. Other scars are meant to be carried on your person like a warrior, a consequence of being in the profession. If there are no scars, then you are not doing enough. But at no point must we allow ourselves to be overwhelmed to the point of giving up or become so hardened or numbed that the experiences leave no mark.