A model I use for decide if something sits well with me or not so well, is to think of the extreme case of the scenario.
For example, I am having a birthday part on the weekend, and I have been decided not to invite some people. As the party has got closer I have started to think that I would have like to have invited all of these people, but I am not convinced about it.
At this point I start to think of the extreme scenario. If I had invited all of the people who are on the fringes of my life, would I mind if there were a few at the party who I was not sure about? Or if I had excluded all of the people on the fringes of my life, would I mind if there were a few missing from the party?
The latter is more likely to cause me regret. I have never regretted having a few extra people at a party whom I am not particularly close to. But I have regretted not inviting people to a party who I have thought were on the fringes.
Thinking in extremes helps, but in this case I have applied it too late. Something to keep in mind for my 40th.