Moish, you are lucky that you have never been in that situation. I hope you never are.
It has been my experience that the people who try to be extra machmir during shiva and aveilut are usually the ones who harbor a lot of guilt. Like, they lacked a good relationship with their parent so they are trying to make up for it.
I know a woman who made sure to say kaddish every day. She is not particularly a feminisit in any way, she had a brother who was saying it…but she felt so guilty about her lack of relationship (or rather, bad relationship) that she tried doing everything she could during aveilut. She was machmir on everything she could (music, haircuts etc).
Conversely, the people I know who were close to their parents and loved them, didn’t really have regrets. So in certain areas they were lenient because they knew their parents would not have wanted them to miss out on certain things. Life is full of tough decisions…