As for 'everything is a disorder' attitude: both sides are right. Partially.
The thing about most disorders is that they are what would normally be a character quirk up to eleven (to use TVTropes/Spinal Tap terminology).
So, if you tend to worry a lot, it is not necessarily an Anxiety Disorder. On the other hand, if your anxiety reaches pathological levels, it may be. If you are kinda sad over a prolonged period, it is not necessarily Depression. If you are 'sad' over a prolonged period, unable to get out of it, and/or you have suicidal thoughts, it probably is.
Also note that being depressed =/= equal just being 'very very sad'; depression is way more complex than that, I do not posess much knowledge to speak about anxiety disorders, but I suspect they, likewise, might be more than meets the eye.
As for myself, if I got someone actively trying to diagnose me with something at all, my bet would go to Paranoia or, more accurately, PPD. In fact, I could probably pass the required number of symptoms needed to diagnose me as such, but I would suspect (
) this would be disease-mongering. Yes, I am somewhat irrationally suspicious of others' motivations, secretive (why am I telling this to you? Because I don't think it's sensitive information. You will never know about THAT), as some may have noticed jumpy when someone attacks me and all that jazz that is, to a degree, abnormal.
I, however, lack the more severe symptoms, and diagnosing from the rest is like diagnosing HIV from flu-like symptoms. In other words, you would only come up with it if you believed I had the disorder in the first place.