Boy, have I ever. Mind you I'm not really that regretful of the email I sent. It was to my brother who was simply not pulling his weight helping me cope with our elderly parents. I was dealing with insomnia, hot flushes, anxiety, depression, but I was still doing everything for them, and he was sitting back hardly even bothering to visit them.
So one night, when my insomnia and hot flushes were really rampant, I sat down and banged out a really long email to him telling him exactly what I thought of his selfishness and laziness. He was very indignant of course and made all the excuses under the sun about having a family and grandchildren and a job and yadda yadda yadda (tell someone who gives a flying %^#$). However fast forward a little, and my father has now passed away and my mother is in an aged care apartment, and now he actually does a lot more.
While I still do most things for her, like shopping etc, he now looks after all her medical appointments, and even does a little bit of gardening in her little courtyard. He still does less than me, but thanks to HRT I'm a whole lot calmer now so I don't get bothered by it anymore. So sometimes ranting as someone can really help though.
Good to hear your boss was understanding.