Severus Snape wasn't one for parties in general, the mere idea of having to chat or entertain someone else sounded utterly useless to him, not to mention boring, mostly considering the common intelligence of wizards these days. However, there were parties he dreaded more, and those were 'old friends' parties, they usually involved a bunch of memories he didn't like to deal with, not to mention the risk of getting tortured or killed, just in reminiscence of what He used to do.
There was still some sort of sense of duty he found himself tied to though, and he couldn't ignore the invitation. He sighed, apparating not too far away from Lastrange's house and quickly walked towards the door, scowling at the cold air, his dark robes flapping with his quick nervous steps.
It was starting to really get cold, he noticed, knocking on the door and waiting, rubbing his hands along his robe, trying to warm up.