On being "too busy" - for me, there is not a number of cancellations or rejections of my invitations that is too much; it's more about how that happens and the results that matter. Anyone local can tell you that I am often too busy. But if someone makes the effort to initiate with me, then if I do want to spend time with them, I will offer an alternate plan or set up a plan to make a plan (like "I'm gonna be busy for the next two weeks but I'll put a reminder on my calendar and ask you when I can predict"). A person can literally say no to every invitation I give and still not upset me, if they offer alternative plans or tell me when to check in again. I have no expectation that people will do otherwise unless I have received permission to expect something from them.
I feel very upset when someone accuses me of not caring because I am busy or late or out of energy; my level of caring has nothing to do with those things. I feel complete understanding with my friends regarding those things. The problem comes in when it is literally all of my local friends because then it just becomes collectively too much effort.
So please, in reading that last post, keep in mind that I am not complaining about any individual event or person, but about a trend in my experiences.