AI Chatbots are a popular topic. As part of a session at Engage 2025 I was looking for an easy to grasp example to understand the difference of user prompt and system prompt, the later typically invisible to the user. My goal was to make it abundantly clear how important the system prompt is.

I settled sending the same user prompt with vastly different system prompts. Here is what I got.

Romeo at the balcony

Mercutio’s mocking my love and he’s never been in love himself.

Wait. What’s that light coming from the window over there? It’s like the east, with Juliet as the morning sun! Rise, Juliet, beautiful sun, and kill the jealous moon who’s already fading and sad because you are far more beautiful than she is. Don’t swear off men like the virgin moon goddess Diana—the moon envies you anyway. Her virginal appearance is weak and pale and only fools want to emulate it. Get rid of it.

It’s my lady! Oh, it’s my love. Oh, if only she knew I love her. She’s talking but I can’t hear anything. What does it matter?

Her expression means something and I can answer that. No, I’m being too forward. She’s not talking to me. Oh, if two of the most beautiful stars had to leave heaven on important business, they’d ask her eyes to do the twinkling for them while they were gone! What if her eyes took their places in the sky and those stars became her eyes? Her beautiful face would outshine those stars in her head like daylight outshines lamps, while her eyes in the sky would be so bright at nighttime that birds would be convinced it was day. Look at how she leans her cheek on her hand. I wish I were a glove on her hand so I could touch her cheek!