Also, letters for people A went to the store and had a run in with F. G witnessed the whole thing, but M couldn't stand up for A because they were arguing with Z. Or DD1, DD2, SIL's BIL's DS's MIL is really really confusing.
And, to add to this thought....even you people who have recurring characters need to explain who people are. It can be as simple as putting something like:
My Aging Aunt (AA) has struck again! AA told my mother that she wants waffles tomorrow morning instead of french toast.
Even if you think we all should know who AA is by now, we may have forgotten what your letters mean. And, newbies sure don't know who it is. It's so simple to just do like newspapers do and put in the full name in the beginning to explain the initials that you're going to use in the rest of the post.
There is a thread at this very moment with a recurring character that I cannot, for the life of me, remember what the initials stand for. It'd be great if the OP could have, at least, expanded it out in the initial post to refresh my memory.
I've said it before, but it bears repeating - YOU know your story inside and out. You know who the characters are. You know the plotline. You know everything about it. But, you can't expect the rest of us to be able to follow your story without giving us a lot of help in defining all the points that you know so well.