Lifestyle arguments aside, startups seem like a _really_ bad deal.
- Dilution. You will get very heavily diluted.
- Shenanigans. There are all kinds of horror stories about the endless methods used to basically screw over the "little people" in startups. A major one is the already extremely rare "successful" exit where you will likely be subject to an extended lockup period (often at least one year) where the stock price will tank and leave you with a fraction of what you had on paper at the time the deal closed. The "big people" get paid first and take huge chunks out of the cash portion of any acquisition at the real value when the deal closes.
As others have noted the ROI on startups for all but the top and preferred equity holders is pretty terrible.
Take cash now.
Employee number 100 perhaps 10 basis points (0.1%)