You shouldn't need a day to celebrate your heritage, you should be able to be proud of it everyday and that goes for every race, creed and country.... When it goes wrong is when people use it as an excuse to be ignorant and jingoistic. Just like you don't need a church or mosque or perceived...
I have no Irish heritage and lost a relative to an IRA attack so don't give two shits about them.
What winds me up is the wife's fourth generation American cousins drinking shots in Michigan called Semtex thinking it's cool and funny... Wankermotherfeckersifyouaskeme.