I've broken a heart, and now I know it was done callously. I went on my way rather oblivious.
Then a few years later had my heart broken badly and it took a long, long time to get through it. When that happened to me I thought back to he whose heart I broke and wish I could go back and change how I handled things. From time to time it still pops into my head about how callous I was and I feel so bad. Immaturity at it's best.