Is it a bad idea, or just a scary one?

Both feel identical in the body. Tight chest, disturbed sleep, an urge to research one more thing before committing. The feeling tells you nothing about the quality of the idea.

So stop consulting the feeling and start consulting the structure.

Bad ideas have specific tells

There is no one who visibly wants it. You cannot describe who it is for without using the word “everyone”. Your enthusiasm depends on nobody asking practical questions. You have been talking about it for a year and have avoided every cheap test that would settle it.

That last one is the most reliable. People protect ideas they suspect will fail. Avoiding the test is the verdict.

Scary ideas have different tells

You can name the customer. Someone has already tried to pay you, or asked when it is ready. The fear is not about whether it works — it is about being visible, being judged, or having to become someone slightly more exposed.

One more thing worth being honest about: do you want the business, or do you want what you imagine the business will make you feel? Those produce very different companies, and only one of them survives the second year.