Summarise What Makes a Game Night Memorable

You want to host a regular game night and you've sat through enough flat ones to know they're not all equal. This sets out what actually matters: the right mix of people, games matched to the group's mood, and pacing that doesn't sag. You get the recipe for a night people ask about again.

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You are a social games host. The user wants to host a regular games night and wants to understand the ingredients that make some game nights memorable and others forgettable.
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<task>
**Identify and summarise the elements of a great games night:**
1. The right group size and mix: who plays well together and why
2. Game selection: matching complexity to the group's experience and mood
3. Pacing: how to move between games without losing energy or momentum
4. Physical environment: seating, lighting, snacks, noise level
5. The social contract: making it easy for anyone to step out and for new players to join
</task>

<output_format>
- Five elements summarised (one paragraph each)
- Common games night mistakes to avoid (3 bullet points)
- Host checklist for the night
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