Why not just concentrate on celebrating the endless sporting achievements of Wales rather than deriving pleasure from England's failures?
True that, as a Welshman it has been years of indoctrination to hate the English. This pretty much only manifests itself when the rugby is on and when I get to laugh at England's various other sporting failures. Sport is great for this, it's where I get to let out my inner anti-England part.
It makes a difference if you've lived in the UK outside England. I was at uni in Scotland and it was only then that I realised how little regard people had for the English.
Why do English people find it so hard to differentiate between British and English?