What does "a sight for sore eyes" mean — and why is it funny?

informal

Meaning

A person or thing that you are very glad to see; a welcome sight.

Where it comes from

An English phrase recorded from the 1700s. The idea is that the sight is so pleasant it could soothe tired, aching eyes.

Why it is funny

The mild humor is the backhanded route to a compliment. To say someone is wonderful to see, the phrase first reminds you that your eyes were sore — the kindness arrives wrapped in a small complaint.

Used in a sentence

"After a week of camping, a hot shower was a sight for sore eyes."