Just by telling him the trails were too muddy to ride. There he was, in a full team tri suit with the local bike shop's logo and racing emblem. ( Our shop gives a good discount on new bikes and parts if you want to fork out 30 bills for a racing team membership, It's worth the money, and most newbs take advantage of it to get a discount on the bike they want to buy. This guy, even forked over for the full team outfit! Stylin, was he! ) We told him we had been riding the multi use, wood chipped trails at the history museum, because the singletrack was way too muddy and you could see it suck the life right out of him.
"Wood chipped" he exclaimed. But with a quick recovery he asked how to get there. It's only a mile or so from the trailhead were we were, but he hopped back in his car to drive to the trails. We continued saying our goodbyes and loading our bikes and as I loaded the wifes bike, I turned my head at the young man as he was pulling out and saw that big grin that comes with the anticipation of riding a bike.