I overheard a woman say to another woman: "I didn't want him coming in, he had blood all down his front". I didn't hear the rest of her conversation and can only speculate as to why he had blood on him:
1) the man had been in a fight.
2) the man had been in a car accident.
3) the man was a butcher.
The first two of these explanations are fairly obvious. The third is less obvious and could (with some thought) be the spark for an original story.