I (a southie) have lived in the North and for about 7 years (Rajasthan, New Delhi) and visited Bihar, West Bengal and Uttar Pradesh. There is definitely more intolerance and close mindedness up north(My opinion). Delhi is the only place we (a group of southies -tamilians, malayalees, telugus etc) had been harassed for being southies. We were called "kallus", "kalias", "madrasee behn c..." etc more than once, am not pointing out one utterance.
Not that there is no intolerance down south, the malayalees discriminate against the tamilians(mallus call tamils paandees etc) and vice versa, but I haven't seen it get hateful down south.
A lot of the North makes a southie truly feel unwelcome (Bihar, Rohtak,Meerut,Mathura etc sure did, Calcutta didn't though)
All the posters who think that this divisiveness shouldn't exit need to get over it. Here in the US there is quite a south/north divide and the Northerners ridicule the Southerners quite often.
So its the opposite in India, the dumb asses are up North and the South is getting smarter, so what?
Just enjoy the ride and try to hang with the southies and maybe one day the guys up north will get out of their stone age mentality