Oh sure, it's a judgement call. I would say as a founder that it's best to seek a high but not insane valuation, and of course the definition thereof depends on

Oh sure, it's a judgement call. I would say as a founder that it's best to seek a high but not insane valuation, and of course the definition thereof depends on multiple factors: what I think a reasonable growth estimate is (while not under the influence of drugs), what the market is currently paying for capital (average, not outliers), etc. If every living multicellular organism on Earth would have to create an account on your service for it to be worth X, X is probably insane. If you have no meaningful revenue, then in most cases a valuation more than one standard deviation among the mean for your sector and maturity is probably nutty.