Stress is the body’s response to perceived threats to life or safety.
When that threat came from a sabre-toothed tiger or a marauding band from the neighbouring tribe, adrenaline would be released, our heart would start pumping, and we would either run away or fight our way out.... or die. The rest of the time, our physiology was in a more relaxed state.
Now, the threat is the boss adding more demands, customers shouting at us, knowing that someone is for the chop and it might be us, being expected to respond to our phones 24/7, or a hundred other things which others have mentioned. Depending on the particular demands and our own capacities and what is going on in the rest of our lives, we may or may not have adequate time to recuperate before the next threat.
If we don’t, then we begin to exhibit symptoms of stress, such as difficulty sleeping, becoming tearful, irritable, digestive problems, substance abuse and so on.
If someone is experiencing these symptoms, and it is their work (or the thought of it) that mainly induces them, then they are experiencing work place stress. You can call them snowflakes all you like, their cortisol levels are probably through the roof.