The thing is you don't have 1% of vested common stock.
When joining the company, you might be granted a set of options which are described as comparable to 1% of total shares, but the number is almost always effectively lower than that.
If the company does well, future funding rounds will lead to dilution of your ownership.
If the company does poorly, VC's will have liquidation preferences meaning that they get paid back first. This can easily bring your ownership down to 0%.
When joining the company, you might be granted a set of options which are described as comparable to 1% of total shares, but the number is almost always effectively lower than that.
If the company does well, future funding rounds will lead to dilution of your ownership.
If the company does poorly, VC's will have liquidation preferences meaning that they get paid back first. This can easily bring your ownership down to 0%.