Some of us have a higher threshold for pain. We can "cope with" far more disappointment and aggravation. Nobody ever said this was a GOOD thing~ and I for one, don't think it IS.
If you're highly tolerant of pain, it means you're somewhat inured (or accustomed) to it. You've grown up having to shield yourself from plenty of emotional setbacks, and have grown accustomed to not only expecting these, but ANTICIPATING them!
Folks like this, are always waiting for the other shoe to drop. They've grown to expect disaster at every turn. When life feels calm and stable, they feel anxious in anticipation of what might disrupt their reverie, and start envisioning all sorts of events that might rob them of that safe, comfortable feeling they're experiencing.
These same people have grown up learning over and over again, an unseen, amorphous SOMETHING can always be counted on, to foil their happiness or glee. This condition is called, GENERALIZED ANXIETY DISORDER.
For these types of folks, it seems they're always in motion (the assumption being, it's harder to hit a moving target). They drive themselves pretty hard, and pay little attention to their human, bodily needs. They live in their head~ not their body. Very rarely (if ever), are the two (mind and body) in sync. They are very typically, disconnected at all times.
In psychological terms, this phenomenological type of event is called, "dissociation." When one dissociates, the mind is not aware of the body's actions and movements. It's sorta like the conscious mind takes a vacation from what's going on in the world around it.
Due to this distinct separation between mind and body, mishaps can easily occur. If you, or anyone you know is "accident prone," this issue is typically the root cause of minor or major injuries to one's body.
We often recognize the phenomenon of dissociation in people who've been thru harrowing physical and/or emotional trauma. Dissociation then, is actually one's survival defense, which blots-out traumatic events to protect the Self~ or keep it reasonably intact, if you will.
If you're Thinking your way thru life, as opposed to Feeling your way along, it's like being outside your body, and not being able to rely on your physical senses (instinct and intuition) to protect you and keep you safe! Metaphorically, this is the same as floating on an angry, turbulent ocean in a small boat not equipped with any oars . . .
you're merely tossed about by gigantic waves that threaten to capsize you, and there ain't a damned thing you can do about it.
You've LEARNED to always be in your head, and prepare fastidiously, for the next few steps that your body wants to take. You're always second-guessing yourself, because making a decision or choice about something (or someone) is only a mental process for you~ never, a feeling one. You second and third guess yourself, because you've never learned how to trust your extra-sensory powers that are there to insure your survival~ but far more importantly, they fortify and enhance your capacity to THRIVE.
I'm only here to educate you. God knows, SOMEBODY has to. 
If however, you're ever wanting to look into dismantling YOUR Generalized Anxiety Disorder, you can read all about it right here on this website ~because thousands of people have rid themselves of all types of anxiety issues (including phobias) and gotten WELL, using the simple tools contained in this ridiculously inexpensive, life-altering course~ and You can, too!
Wouldn't it be utterly fabulous, to stop feeling afraid of the future~ or anything ELSE for that matter??