It’s Valentine’s Day, named for one of three saints of the Catholic Church, none of whom can be verified, so they gave February 14 to Sts. Cyril & Methodius. But that’s a story for another day.
"Be Careful, It’s My Heart" is a song by Irving Berlin that he wrote for the 1942 movie Holiday Inn starring Bing Crosby, Marjorie Reynolds, and Fred Astaire. The idea behind the movie was that Bing leaves a successful act to open a hotel in New England that’s only open on holidays, for which he puts on a show. This was the song for Valentine’s Day.