But they're a minefield of potential humiliation. They provide the perfect opportunity to reveal our confusion about plurals and possessives.
Happy holidays from the Smith's.
To the Thomases'.
We look forward to visiting the Garcias's house this year.
It just wouldn't be Christmas without all those flubbed plurals and possessives on holiday cards and, worse, on personalized gifts like doormats and placards that welcome visitors to the home of "The Jones's."
But unlike those fumbling attempts profess how much you "love" your new Snuggie, these catastrophes are avoidable. Just remember the things you already know about plurals and possessives, and then take it slowly.
Say, for example, you're Smith. The rules of plurals tell us that, when you're talking about more than one Smith, you add an S: the Smiths.
That's different from possessives. To show that something belongs either to Smith or to all the Smiths, you need to remember the rules of possessives. For singular words that don't end in S, you form the possessive by adding an apostrophe and an S. The dog's tail. Smith's house. For plural words that end in S, add only the apostrophe. The dogs' tails. The Smiths' house. Those freak plurals that don't end in S, words like men, children and deer you treat just like singulars: add an apostrophe and an S: the men's department.
So if the person you're writing to or about has a name not ending in S, ask yourself whether you want a singular (Smith) or a plural (Smiths). Then, if you want to show possession, note whether it's singular possessive (Smith's), or a plural possessive (the Smiths').