Happy Towel Day 2019!
Towel Day is a tribute to Douglas Adams and takes place on May 25th, two weeks after Adams' death on May 11, 2001.
During the Towel Day fans of Adams carry around a towel all day, because of significance of towels in Hitchhiker's Guide to the Galaxy:
More importantly, a towel has immense psychological value.
For some reason, if a strag (strag: non-hitch hiker) discovers that a hitchhiker has his towel with him, he will automatically assume that he is also in possession of a toothbrush, face flannel, soap, tin of biscuits, flask, compass, map, ball of string, gnat spray, wet weather gear, space suit etc., etc.
Furthermore, the strag will then happily lend the hitch hiker any of these or a dozen other items that the hitchhiker might accidentally have "lost."
What the strag will think is that any man who can hitch the length and breadth of the galaxy, rough it, slum it, struggle against terrible odds, win through, and still knows where his towel is, is clearly a man to be reckoned with.