Magic: The Gathering Thread XIV: Instant Annoying, Just Add Hexproof

[Thanatos 51-50]

Elaborate, please?

Priority passes after the mana costs have been paid, which is really when you want to take priority, anyway, because if you cast a counterspell before they pay, then you're not hindering the enemy at all.
However, one can concede the game even if they do not have priority, and it is, AFAIK, the ONLY thing that trumps priority.