A lack or deficiency; it's said to "make the heart grow fonder"
[DOC] [TLE] The Man Who Lied to His Laptop - Penguin [PAR] It's much harder to figure out why things are going wrong and how to improve 
them .... And a user who despised eye candy in software said, I wish all 
software .... For example, absence may make the heart grow fonder, but never 
seeing ...