What is the definition of a ''Stress'' Snake?

What is the definition of a ''Stress'' Snake. I guess it varies. I'am not having no problem with our new baby so far, but in your point of view what is a ''stress'' snake? I like know what kind of sign's to look for in future purchases or even my own if something looks wrong.

Hissing, a lot of activity during the day (not hiding - a hiding BP is a happy BP), striking, not eating etc etc

A snake can hiss when it just wants to be left alone, not necessarily when it is stressed and is its way of warning you to go away, I tend to ignore this unless the BP is showing severe signs of stress. Some BP's are more active than others but if you rarely see your BP it is actually a good sign! Striking the enclosure or at you can also be a sign of stress and that your BP feels insecure, frightened or even hungry! And some stressed BP's will not eat.

I'm sure there are other signs but these are the ones which come off the top of my head :)

I've never experienced it, but I've heard over soaking could be a result of a stressed snake. Again, I've never experienced it, but my research suggests this can be caused by issues with mites, low humidity and/or high temps.

When it comes to ball pythons

Aggressive behavior
Food refusal
Being active in the day time