An idea is useless. What it matters, especially in SAAS is to identify a need of an heterogeneous group of people. A painful one for which they would pay a certain amount.
So instead looking for an idea try looking for a community and try to understand it. Study it, see what they do, how they do and what they really need. Don't ask them what they need, or if they have an idea because they might not know.
Once you understand them you can start crystallizing an idea. It might be bad, you start (in)validating assumptions, pivotating and iterating through those steps until you reach to the good "idea".
An idea you get from somebody else is in the best case scenario one which identifies a need. You still have to validate it, which is the hard part. And you still have to understand your customers which is even harder.
The successful one man side-projects are successful because they are started by passion by people who follow those steps sometimes without even knowing it. They are annoyed by something or they need something which does not exist. They create it first for them and for people like them.
