14. "Everyone's sad sometimes. You'll get over it."
Again, there is a tremendous difference between sadness and depression. While people will get over normal bouts of sadness, people will not always get over depression - and if left untreated under the expectation that it will pass, the condition could lead to a terrible result.
Telling someone that their depression is simply something to get over invalidates their experience, and when people feel as if they are "crazy" or "making up their depression," they are less likely to seek help. When those with serious mental illnesses do not seek help, the cases often escalate and become difficult if not impossible to reverse.
Alternative: Let the person know that what they are feeling is not just a normal case of the blues, and suggest that they seek help to cope with their condition. However, if they do not agree, respect their autonomy and do not push further.