You find a patch of edible funghi. They taste well and all, no ill effects. UNLESS you consume some beverage, even 3 (three) days after eating it. Then you become really sick with pains, vomiting, all the fancy stuff. As a gift or good meal, it could be a cruel joke or to make sure the heroes spend their time focused on the mission. And the fine soup you had in the inn yesterday could have some in.
(Inspired through a real-world fungus. Was really used to cure alcoholism.)
What a narrow street! The bowed windows of the upper floors encroach on the view of the bowed windows opposite, making it all very dark and shady down here in your carriage. You feel it slow down and stop, and there are raised voices outside. Craning your neck out of the door you see a smug cartsman ahead, whose cart is blocking just enough of the narrow street to make your passage impossible. He appears to be waiting for you to move, but your driver is hurling abuse at him and your horses are getting restless...