Funniest? Well, Tango flared at pretty much everything when I first got him. If it moved, he flared at it. Made me laugh. And he's not afraid of anything. You can grab him in a cup, pet him, prod him, he stays right with you. That makes me smile.
Scariest? It wasn't for him. He's been healthy and happy for these 8 months. But when I first got my three cories, I was terrified that he'd hurt them. He bullied them a bit and I was ready to pull him out. He quickly lost interest when they didn't respond but it was a tense 15 minutes.
Sarcastic? Sometimes when it's close to his feeding time I can literally feel him staring at me. I look over and he's at the corner all...
... feed me. Just today I had to stop him from chasing one of the cories and as I came towards the tank he shot up all innocent to the top like he wasn't doing anything. Or he wanted to be fed.