I've noticed something...

[Truth in Ruin]

I think I'm on to something here.  In my experience, it seems that the borderline is happier in the morning, and more emotionally distraught at night.  Maybe it's just what I have experienced.  I thought it was worth noting at least.

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[briefcase]

This is probably true, but maybe not so unique to BPD.  I would guess most people are more irritable at the end of the day when they feel tired or hungry.  Of course, people with BPD have extreme and unstable emotions - so the effects get magnified. 

[Truth in Ruin]

Good point briefcase.  I do find myself less emotional at night because I'm too tired to care, so maybe the BPD person sees that, and they don't like it?  Anyway, maybe I'm reading into it too much, but it did seem like my EX and I had more problems at night.

[tiff]

My SO wakes up in a bad mood usually - all night nightmares often set the tone.  Mornings are pretty rough and it's hard for me to deal with an angry person when I'm barely awake. 

[Chosen]

When H's dysregulated (like now), mornings and evenings are just as bad.  He'll do anything to make us both miss work (I used to fall into the trap in the past.  Now I don't) in the morning, and he'll do anything to keep us from sleeping at night.