When my grandmother was little, her parents and grandparents raised much of their own food and built their own furniture. I was imagining living in that time, and being called lazy. I am tired so often, but it's not really a recognized ailment. I hide it now, doing a sedentary job, and not having an active social life. But when my grandmother was little, perhaps I could not have hidden it so well. And people can't see that I'm tired. They assume that all bodies work the same. That I have the same amount of energy as they do, so if I'm not as active as they are, I'm just being lazy.
I am very fortunate not to live with chronic pain, but some do. And if such people are cranky and unenthusiastic at times, others think it's a character flaw. They don't realize that they'd be cranky and unenthusiastic too if they were in pain all the time.
Likewise, if someone is suspicious, paranoid, pessimistic, fearful, maybe that person has lived through years of betrayals.
Rather than think less of people for their apparent character flaws, let us have compassion for the suffering that got them that way.