I'm a very positive person. I complain a lot about little aches, pains and curiosities but that doesn't change who I am.
I try to see the best in everyone. I'll make excuses for them to explain away words or behaviors that irk me. If people continuously wrong me or wear me down, I distance myself. I can go years without speaking to immediate family members (mom, dad, siblings). It's not because I'm mad at them or don't love them, they're simply "psychic vampires". Being around them, under certain conditions, sucks all energy out of me and throws Chaos into my mind. I loathe chaos.

But, I understand what you mean about the thoughts. Despite all of the above, I have a very real dark side. In years past, I could lose myself for hours in daydreams about the worst of things happening to me or people I love. Eventually, I said enough. (I was close to 30 years old by that point.) Whenever my thoughts would venture somewhere negative, I'd tell my brain to shut up and I would have to make a very conscious effort to redirect my thoughts. I was amazed when I had to redirect them several times within 1 minutes time.
It took months, but I eventually gained control. I had to be very firm with myself though.
In times of stress, it's easy to fall back into the negative fantasies.

Are you under more than the usual stress? Have you experienced any sort of major change in your life within the last couple months (job change, new home, new relationship, illness)

As for negativity being more honest. ??? I think, to some extent, we chose our own reality. I feel it's healthier to try to see beyond the persona a person projects. I read body language and try to pick up on other cues that point to the motivation behind a persons words and actions. I try not to let others make me behave one way or feel another. That's not to say it NEVER happens, lol, but I try and am mostly successful.