The combination of alone and in a closed area could be related to a form of claustrophobia, so determining whether it's in all closed areas that you feel like crying is a good idea. Also whether the size of the area is important or the feeling of being alone is more important.
Lastly, crying has a purely social function, Bylsma says. It often wins support from those who watch you cry. Sometimes, crying may be manipulative -- a way to get what you want, whether you're asking a friend to go shopping with you, your spouse to agree to a luxurious vacation, or your child to get their math homework done.