The main purpose of sign of course is to communicate, convey information and assist the receiver with decision making based on the information provided.
They provide guidance when the road is wet, slippery, or indeed undertaking roadworks!
but then again - there are these signs!!
Product - Metal Retro Sign - Common Sense
Predrilled
20cm x 30 cm
Sign reads " Warning - My sense of Humor might hurt your feelings! "