I remember Decimal Day in 1975 too - best thing ever happened imho.
I really struggled with adding up bills and counting change, as a boy in Ireland and England...19/11 + 2/3 +17/6halfpenny etc..aaarrgh! Thank god for decimalistaionI say. Yes, I know some people used it as an excuse to put up prices etc - but folks have always found ways to do that!