Okay, so you know that moment when one of your fandoms is mentioned in another of your fandoms? No? Well, let me give you an example that got me most excited:
I was just watching Arrow (I just started recently and I'm in the middle of the first season) and OLIVER MENTIONED FALL OUT BOY! Yes, there was mild excitement involved. Perhaps a squeal or two. No stopping mid-episode though to express my feelings. Pfft, no, I'd never do that!

Oh god, a further update: LAUREL'S MUM IS PLAYED BY RIVER SONG!! 😱😱😱
The excitement right now is real. Maybe the odd fangirl attack here and there as well xD now two of my favourite Doctor Who characters are also both in Arrow, and this is very exciting.