Many athiests are VERY intelligent human beings but they lack the will or the desire to see the truth.

[quoted from the London Atheist Bus Campaign] " There probably is no God, so stop worrying and enjoy your lives "

Well, one way to refute that quickly and simply is to bring people's attentions to the fact that its actually very hard to enjoy a life without God...
The world sucks, we can all say with 100% confidence that no-one can find any fulfilment anywhere on this Earth except from God, who is not from this Earth. Can anybody see where I'm going with that? But how do you say that succinctly...hmmm?