Originally Posted by RadioGirl

Add more detail about the highlighted sentence and you'll be waved through quick-smart!

I did something like at Immigration in NZ once; I was sleep-deprived after too many late nights but all geared up to give a conference talk on the really exciting part of my project, so when the immigration guy asked "reason for visit" I launched into it. After two sentences he gave me back my passport and said, rather forcefully, "Welcome to New Zealand. NEXT!!!"