No matter how cute the puppies in these pictures are, don't get fooled - these dogs are on a serious mission.

The top job roles for the doggies are: police dogs, military dogs, fire dogs, guide and hearing dogs, medical assistance and disability dogs, and therapy dogs. Most canines at work are Retrievers or Golden Shepherds, because they're known for being smart and easy to train.

The noses of service dogs are 50 times more sensitive than a human's, which really helps pooches in police and fire departments. Police dogs sniff out drugs, detect explosives and find missing people or objects while using their nose. Likewise, firefighter doggies detect ignitable substances and point to the cause of fire, especially in cases of arson.

Their 'vest' is not just a cute outfit - it's their uniform. It informs other humans that the dog is on the job. Remember - despite the urge to reach out to them, you should not pet, feed or talk to the doggies at work. They're doing a serious job that all of us should acknowledge and appreciate.