Some things never change. History repeats itself. New becomes old becomes new becomes old again.
I'm never sure whether any of the above is a good thing or a bad thing. People change, little by little, but some factors will always stay the same. It's a great little faculty of life, and it means that if there was something you liked about someone when you first met them, it will probably always be there, ready to make you smile at a moments notice. Unfortunately, the same goes for the things you don't like about someone. It's a bit like Feng Shui, only with people instead of furniture. Get it right, and a jolly time can be had by all. Get it wrong, and the Dragon of Unhappiness might well bite you in the proverbials.
That said, when you've spent the time running up to an event worrying about who will be there, and what they'll do that will make you want to cheerfully slap them, it takes the wind out of your sails (in a thoroughly pleasant, positive manner) when everything is great, the atmosphere's utterly positive and it genuinely is good to see people again.
Sometimes it's nice to be wrong about people.