Below is an explanation of some of the most common behaviors associated with BDD. Some people may display more than others, and to varying degrees, but they tend to be common among those suffering from BDD.

Mirrors: Checking and Avoidance
One of the most common behaviors displayed by a BDDer is mirror checking. Any mirror will do, along with reflective surfaces such as store windows, although most BDDers will have a handful of favorite mirrors that are in places with, what they consider to be, the most appealing lighting. I've heard more than once that the lighting from late morning until early evening create the greatest amounts of distress. Such light shining in a window seems to de-emphasize facial features, making them appear akin to a human blob. This often causes the highly perfectionistic BDDer to assume his face has morphed into a horrendous monster, whereas most people would just blow it off as the fault of bad lighting. Many BDDers prefer to avoid mirrors during this time of day.

Although BDD is associated with long hours (in the upper single digits) spent in front of the mirror, I've found that over the past few years, I've started spending less time sitting statically in front of one reflective surface, but instead, check only momentarily several times a day. I consider this a great improvement. Many people affected with BDD find that they avoid mirrors altogether, covering them, taking them down, or turning off lights when they approach one. Most of us have a love/hate relationship going on with mirrors, as they can sometimes reflect an image that is better than what we had in our minds. At other times, we are feeling confident, but then see our reflection and fall into deep despair. What must be remembered is the fact that this mirror checking is not the source of pain. Often, a person with BDD can spend time in front of a mirror and feel no associated torment. But, things become a problem when a BDD attack accompanies this mirror checking. A BDD attack is a BDDer's worst enemy. I use this term to describe times when you feel hopeless, ugly, deformed, and suicidal, and it can hit at any time and be triggered by a number of situations. Because the likelihood of a BDD attack often occurs during stressful times, you will find that your other BDD behaviors, such as mirror checking, will most likely increase as well. Therefore, many BDDers find that they associate this self-hatred and hopelessness with mirrors, and the reflection they see staring back at them.

Cameras
Another common BDD complaint deals with photographs. Many a BDDer has avoided intimate family gatherings or other important situations just to prevent themselves from being photographed. They say a picture is worth a thousand words, but to a BDDer, it is only one: disgust. Having your face caught on film creates much distress, as we become paranoid as to who will see it, what they will think, and feel ashamed that anybody would have to look at us. We have no control over who will see the photo, and what will go through their minds when they see it. A photo almost always convinces a BDDer that their image of themselves, in their own mind, is correct, if not worse than they thought. In my opinion, this shows that BDDers do see themselves just as everybody else does. They've just come to despise what they see, and have become extremely perfectionistic, zooming in on even the tiniest details of their appearance. They do not hold these same standards towards others.
The interesting thing is, BDDers opinions of themselves in photographs can change from time to time. Sometimes, they will even see a photograph of themselves that they actually like. I have found that I've hated certain photos in the past, to realize that they actually looked decent, to find that I hated them all over again when they were presented to me at a further date! Perhaps this has something to do with what we are focusing on in the picture, as our body part that we are obsessing over changes from day to day. If a certain photo doesn't emphasize this hated feature, then we can view it as a decent photo. If the feature is entirely minimized by having the picture shot at a unique angle, then we might even like the picture. But most BDDers do not want to take a chance being photographed, as looking at one they consider to be bad can bring about a BDD attack. I would say that most of our obsessive behaviors, such as avoiding cameras, are an attempt to keep BDD attacks at bay.

Public Situations
Many BDDers have problems in public situations. Some even have problems meeting with relatives and family members. I know that every time I am at a family gathering, I run to the back of the house and lock the door because I am too afraid of judgment. When seeing my immediate family after a month of being out of contact, I will shake uncontrollably. Most BDDers find that they are very uncomfortable in social situations for several reasons. They first feel strangely inhuman. They have a difficult time truly connecting to other people, and usually feel like an outcast. Their natural body language is often restricted, because they feel stressed that the people around them might observe them and judge them unfavorably. It almost seems narcissistic, feeling so singled out from the rest of the public, yet at the same time, we do not feel that we are separated from society because we are better than anyone else. We feel almost as if we do not exist, and that we are separated from the rest of the human race. It feels as if we, to use the old cliché, stick out like a sore thumb. We are scared to say the wrong thing, move the wrong way, smile, or even blush, because we fear that everyone is observing us, noticing how different we are, and we will be scrutinized and judged, and ultimately rejected. Because of this fear, some BDDers will not leave the house during daytime hours, as they feel others will have a better chance of judging them. Others will drop out of school, be unemployed, become agoraphobic, or just simply avoid any situation where people can be found altogether. Some BDDers will be able to hold down a job, and keep a social life, but most are constantly worrying about what others think of them, and believe they come across much less confident than they really are. They harbor feelings of inferiority, and it causes them much distress that is often unseen by outsiders.