Don't know & can't trust

There is this concept of emotional thresholds that has been brought up recently. An emotional threshold is a threshold which designates how much emotional strain somebody can take before they are unable to do something.

For example, I have a friend who says that in high school he was unable to do tedious school work. I have another that claims he is unable to commit to something and pursue it (in a somewhat fatalistic/depressive manner). I have another (that from my understanding) claims that the shuns of her peers aroused an enormous rage and lasting bitterness within her.

With this criteria, how do I decide whether someone has an weak emotional threshold, or is just complaining like a bitch? If someone decides to say that their (said thing) is the reason for their problem, I'm unable to deny it, because I am not them, but I'm also unable to believe it, because when put into retrospect, the reasons are extremely difficult to believe. The easiest solution would be if I didn't care-- but i'm human, and because these people are my friends, I attempt to understand (to no avail). This concept disturbs me immensely because it raises the issues of validity (regarding the issue) and the distribution of respect (in correlation to their strengths: emotional thresholds/motivation) I appropriate towards each individual.

As a friend, I'm also supposed to be able to trust and accept the variety of different behaviors. However, if my friends decide to complain or raise their issue as a means to vent, I'm not horrible enough to simply shut them down, but I find it incredibly grating to just sit by and listen to their inability to surpass their utterly terrible emotional threshold.

People: in-compre-fucking-hensible...