A tramp walked into a cafe and asked for a toothpick. was given one then he went back outside.?

seconds later, a second tramp entered the cafe and asked for a toothpick. was given one. then he also went outside. few minutes later when a third tramp came into the cafe and asked for a straw. the waiter asked why did he want a straw when the others had asked for a toothpick. the tramp replied"someones been sick outside and the other two tramps have already picked at the best stuff.