This may sound strange coming from a photographer but there’s nothing worse in a photograph than an obviously put-on smile or a forced pose. We’ve all either done it or seen it.
And that is why good photos of animals (technically correct – in focus, well lit, etc.) stand out so much. They’re natural; What you’re capturing is their everyday behaviour at that moment in time.
Now some (lucky) people are naturally photogenic but if that’s not you, next time someone’s got a camera, at least try to ignore it and trust the photographer to catch you looking your best.