For such a small island, the diversity in accents is immense. It's almost like every city or county will sound different from the next. Perhaps because you're not from here you wouldn't be able to tell what accent is from where. Same can be said if you came over here, we'll know you're either American or Canadian but which one and from what part would be difficult for most.
No I don't think the English hate the Welsh. Do I think the Welsh hate the English? Probably not as much as the Scots or the Irish. It's not hate, our rivalry is only really highlighted in sports. Any 'hate' will be from nationalists, or idiots at a football or rugby match.
Ask me again when Wales play England in the Rubgy World Cup, I'll probably give you a different answer if we lose.