Know what you mean!
Have a neighbour who became a friend, but she is what is known as a "toxic" person - really can bring you down, as she is very, very negative and seems to thrive on being one of lifes victims.
It's difficult to avoid her as our children are at the same school too, and as I am essentially a nice person (I hope), I could never be outright rude or unpleasant, and I don't want to hurt her feelings.
It gets difficult for us when we have things like barbecues, as I would love to invite another friend that I have me through school, but then I worry about how the "toxic" one would react if she wasn't invited. Her DH is a bit of a knob too, and socially, they can both say things that can make me cringe.
I am really quite a tolerant person - I have a mixture of different friends and people with different tastes, and I love to have that mix.
I get annoyed with her as she can be rude to people too. She has done that nudge/comment thing that some mums love doing in the playground too, and I hate any playground nastiness. She holds grudges and is very judgemental. In fairness to her, she has had a catalogue of awful things happen to her, but I still don't think that this excuses all of her behaviour.
God, I obviously needed to get this off my chest! I did try to talk her into moving abroad out of desperation....

Think I'm just going to have to grin and bear it, until she steps over the line in way I cannot ignore. She's already fallen out with a former friend on the street - wasn't her fault of course, as it never it 