Tears of joy.
"Tears of joy" refers to crying when there has been a psychological gain, not a loss. The dynamic explanation of the phenomenon is that the need to repress sadness is lifted because of the gain; genetically the crying is over past losses. A clinical vignette illustrating the phenomenon is given here. It relieved the patient to be told that her symptoms did not mean that she was sick and requiring medication.
D000328:Adult; D003863:Depression / Q000523:psychology*; D005260:Female; D006240:Happiness; D006801:Humans; D008297:Male; D008388:Marital Therapy; D013666:Tears