Festivity Level 1:

Your guests are chatting amiably with each other, admiring your
Christmas-tree ornaments, singing carols around the upright piano,
sipping at their drinks and nibbling hors d'oeuvres.

Festivity Level 2:

Your guests are talking loudly -- sometimes to each other,
and sometimes to nobody at all, rearranging your Christmas-tree
ornaments, singing "I Gotta Be Me" around the upright piano,
gulping their drinks and wolfing down hors d'oeuvres.

Festivity Level 3:

Your guests are arguing violently with inanimate objects,
singing "I can't get no satisfaction," gulping down other peoples' drinks,
wolfing down Christmas-tree ornaments and placing hors d'oeuvres
in the upright piano to see what happens when te little hammers strike.

Festivity Level 4:

Your guests, hors d'oeuvres smeared all over their naked bodies
are performing a ritual dance around the burning Christmas tree.
The piano is missing.

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You want to keep your party somewhere around level 3,
unless you rent your home and own Firearms,
in which case you can go to level 4.

The best way to get to level 3 is egg-nog.