It’s been hard to trust commercials claiming to feature “real people” ever since Applebee’s did one with the dad from Nickelodeon’s My Brother and Me. Car commercials are particularly prone to this type of marketing, often adopting a format where some company man extols a vehicle’s meaningless awards and misleading price as observers nod politely and mutter inane pleasantries. Last week, we shared a few of sketch comedy group Zebra Corner’s skewering of the real people concept, and now Boston loudmouth “Mahk” is back for another round.