New Generation, New Language

I referred to one of my friend as "Yaar" (Hindi of "friend") when I was in standard 5th/6th. My father did not like it as "Yaar" was perceived as a not-so-good language then, at least in my family. Few days back, I just hurt myself while playing with Muntasir & he immediately responded "It's OK yaar". Instantaneously I was taken aback, remembered my father's look, then realized it is something Muntasir probably has learnt in the school & then replied back to him "OK yaar, let's continue playing then". Since then, we have been telling "It's OK yaar" to each other, when one sees the other one upset, it has become a fun now. 
P.S. This is not to argue if my father was right or wrong, but the chemistry in a relationship is continuously evolving & we have to be adaptive to that...