Aside from the very obvious extreme health or money worries which of course would cause anyone a great deal of stress.
But aside from that, I grew up with one extremely stressed parent and one pretty much absent parent.
My extremely stressed parent gets stressed about the most minor things you can think of (running out of milk etc), and also gets stressed in the catastrophising sense - so they worry about what could happen, not what has happened or is likely to happen.
All of this is very hard to live with as a child/teen and I seem to have turned out opposite. I guess somehow subconsciously I do everything different to her because I don't want to be like her - so this manifests itself in almost everything.
Even when I had a hugely stressful job it didn't make me stressed. BUT Christmas and holidays (finding holidays and packing for holidays) make me stressed. That panicky feeling.