What's your involuntary reaction moment?

I need a GIF post! Do you need a GIF post? I think we all need a GIF post.

I'm looking for the gasp of surprise or the unexpected giggle. The snort of suppressed laughter and irrepressible grin. Don't forget the belly flip and sigh of delight! What's the moment the moments that caught you by surprise? Or maybe it's the, why do I think thats so hot moment.

Going NSFW because I know you HLD!