Coz it shows their personal feelings for each other, what they really think inside, True colors came out.
In my Opinion all are great singers and i love their singing but in real world to win anyone's heart you have to be true honest and real human being. You cannot become any kind of JODI of the world; you cannot win any fight, unless you're a good person. (US) janta watch your every little behavior, the way you respond, you talk, you criticize, you judge, passing comment, showing curtsy, being polite, and respecting others. These are very important values that we Janta expect from any actor, singer, dancer director politician etc. and the list is long.
Unfortunately, We didn't see a lot of above mention Ethics values in REX and ARPITA so therefore; they are frustrated and leaving bad impression on public.
If any of my friends at India-Forums are not agree feel free to write me.
Imran.