How to find your passion (and a good SaaS idea)
The way out of both questions is the same move: stop asking yourself, and go read a record.
The statement heuristic
Pull up your card statement and sort the year by merchant. Skip rent, utilities, groceries — the obligations. What's left is a ledger of what you choose when nobody is watching and nothing is forcing you. The category you keep paying for — gear, courses, entry fees, tools, books on one subject — is not what you say your passion is. It's what your own behaviour has already recorded it to be.
The statement can embarrass you. It's supposed to. If it says the money goes to a thing you'd never put in a bio, that gap between the stated and the revealed answer is exactly the information introspection couldn't give you.
The spreadsheet heuristic
The SaaS version of the same move is David Sacks's:
@DavidSacks
Good heuristic for creating SaaS startups: find a commonly used spreadsheet (eg cap tables) and turn it into a dashboard (eg Carta). Replace email attachments with workflows. Spreadsheets are the long tail of datasets that don’t have their own SaaS tool.
Dec 2018
A hand-maintained spreadsheet is the business equivalent of the card statement: a record of need, kept up not because anyone enjoys it but because someone needs the answer badly enough to fake the software by hand, cell by cell. You don't have to guess whether the product is wanted — the spreadsheet's existence is the evidence, the way the statement's totals are.
Two different questions, two different records. The statement is about you; the spreadsheet is about somebody else.
When I ran the second one, I went hunting for a spreadsheet worth replacing and started noticing how people abuse them: Goal Seek dragged back and forth until the model says the number you need, and the trail of saved copies — v1, v2, final, final-FINAL — because a sheet forgets the instant you overwrite a cell. That second abuse pulled a thread that ended somewhere I didn't expect: how a book should store an editable present alongside a past you can trust, and what accounting software looks like when the ledger is derived from its inputs instead of typed in by hand.