Has there been a toy, invention, or any retro product you regret using?

The Snoopy Sno-Cone Maker and the revival of Gee, Your Hair Smells Terrific are those I regret trying out. I'll expain later.

Hidden Treasures cereal they tasted horrible!
Flutter Ponies; the wings fell off the pony!

Multiple old video games. That's about it.

Action 52 was one I regret playing.

I don't know that I regret trying any, because otherwise I wouldn't have known how I felt about them. But, I can say there are a few that were decidedly not good products.

- Several old video games (ex: Blades of Steel)
- Some beverages that I thought I remembered tasting good (ex: RC Cola)
- Various food offerings making a "comeback" (ex: Burger King's Italian Chicken Sandwich)

Moxie soda springs to mind.

I regret playing some old PS2 games I bought online or at garage sales (ex. Britney's Dance Beat) as well as some GBA titles (ex. Hot Wheels Velocity X).

Friday the 13th for NES.