I'm not saying you'd want your doctor making a joke when they're telling you that you have cancer or something, but it's good to try and lighten the mood when appropriate, especially in certain professions.
This is especially true of police officers. Because, depending on your personal experiences with cops, these guys can get real scary and real un-funny, real fast. But the fact that some cops are able to joke around portrays them in a more humanizing light, and because of that entertainment value, you'll be more likely to cooperate with them and turn to them for help.
Which might be the reason why the New South Wales Police Force have such an incredible Facebook page.
They're not only posting photos of cute doggies either, but hilarious memes to boot. And I can't tell if this "meme team" post is serious or not. All I know is I love it.
What's probably the most impressive part about the force's memes is that they're pretty current.