I perform a lot of physical labor around our place, and am often repairing equipment or vehicles. I always make sure I am presentable when I go on errands to buy parts or supplies. Back home nobody cares all that much, people just think to themselves, "looks like he's been working on something", but people here take care in their appearance. One day I ran to buy fuel without cleaning up and changing clothes, and three Thai school girls were just parking their motorbike at the pumps. When the driver saw me she wrinkled her nose and said in Thai, "he's so dirty!"
As far as smelling like something goes, I have never heard of the locals saying foreigners smell like wet dogs, I have heard it said that they smell like butter...and that certainly wasn't meant as a compliment. In their own language and customs calling someone a dog, or dog face is extremely offensive.