How do you listen in each case? Are there any differences?
With the holiday anecdote, your main concern was probably understanding the general idea and knowing when some response was expected. In contrast, when listening to the directions to a party, understanding the exact words is likely to be more important – if you want to get there without incident, that is!
The way you listened to the holiday anecdote could be characterised as top-down listening. This refers to the use of background knowledge in understanding the meaning of the message. Background knowledge consists of context, that is, the situation and topic, and co-text, in other words, what came before and after. The context of chatting to a friend in a casual environment itself narrows down the range of possible topics. Once the topic of a holiday has been established, our knowledge of the kind of things that can happen on holiday comes into play and helps us to ‘match’ the incoming sound signal against our expectations of what we might hear and to fill out specific details.