I am always intrigued by one phenomenon in life: how injuries leave scars (while pleasure often does not).
This seems to be the case not just for physical injuries but also psychological and emotional ones. Like the concept of scarring, it seems like nature's ways of "forcing" the individual to not forget. This is the reason why it is easier for most people to name the most embarrassing/disappointing memory as compared to moments when they are the happiest.
As an educator, I got to work with an amazing lot of people. Students come in different colours, shapes and sizes and of course, from different backgrounds. Since I was teaching in a neighbourhood school (i.e. not a "prestigious" school), I got relatively more exposure to students from more challenging backgrounds and also, disciplinary issues. While working with these thirteen- to seventeen-year-olds, I observed how some youths acted out as attempts to cope with their pain and struggles. Fast forward to today when I am no longer a teacher, I do still hear of victims of previous poor decisions by others (e.g. bullying) or self (e.g. picking up bad habit/company) struggling to deal with the painful experience faced in their teens.
At the individual level, I believe that we can advocate the use of pain as a motivator or an opportunity to develop mental strength. We can try to use painful memories constructively and derive new strengths so as to emerge from the experiences stronger.
However, at a societal level, it is important for everyone to recognise that pain lasts longer. Some experiences can prove so traumatic that one could never really walk out of them. Never dismiss others traumas as a trivial lack of mental strength even if you indeed believe to be so. The fact remains that while we can attempt to empathise with the feeling of others in their situation, we can never fully appreciate the exact magnitude of it. Similarly, we should also not expect others to be able to feel what we are feeling. This is why I would think that sometimes it is better to say "I can only imagine how that would have felt" instead of "trust me, I know how that feels".
In all, while I do not advocate the use of the "tender-loving-care-only" style of education, I think we need to always be mindful of the consequence of pain for it is fast to hurt and slow to heal.
All wounds heal with time. But they leave scars.