Prayer: Does Crying Invalidate Wudu?

Question: I was told that crying not from khushu3, nullifies the wudu', is this true? And if one finds food bits stuck b/n the teeth after performing wudu', is the wudu' still valid?

Walaikum assalam,
 
Crying invalidates the prayer, if from other than remembering Heaven, Hell or other next-worldly matters. It does not invalidate wudu.
 
What invalidates wudu is laughing audibly in prayer.
 
Wassalam,
Faraz Rabbani