Why do I always lose at bonus rounds?

[Vaxilda]

Is it just me or do bonus rounds on online casino slots seem like they’re set up to make you lose?

 

[MisterMiyagi]

This is exactly what is happening to me too. I've only won a bigger prize than the actual bet.

 

[LeBonRoll]

Omg me too! Never won more than I started with on a bonus round