A lot of my regrets are about things I've done to affect others, rather than things directly impacting my life if that makes sense. Most of my own personal regrets I've at least learnt from so I can't begrudge those experiences too much .
One in particular was a boyfriend I had in my very early 20's. He was in his 30's and I very naively got involved in a relationship with him knowing full well he had strong feelings for me and wanted a serious commitment, while I did not see a future for us. Six months (yes, six) down the track and I decided I just couldn't do it anymore, so I went to his apartment while he was at work, grabbed my stuff and left his things such as toothbrush etc, and wrote a note saying sorry I didn't love him and not to call me anymore. Well of course he did call me repeatedly and when that didn't work he started coming over to my place and demanding to know what happened?! So stupid 21 year old me then started using my housemate as a buffer, telling him fibs about my whereabouts, and just generally behaving poorly without giving him the courtesy of a face to face discussion to explain my feelings. I eventually faced him about three weeks later, unbelievably he still wanted to give the relationship another chance but I stood firm and then had to admit I didn't love him and never did. He was gutted and was crying, all I could do was sit there and dumbly hold his hand and say "sorry" repeatedly.
A shameful chapter in my life and something I haven't actually told anyone before. I still feel incredibly guilty and ashamed about my immature and thoughtless behaviour that hurt someone so much. :-(