Finding out you owe a metric ton of cash to the fed? Expensive.
Receiving a tax nonpayment notice from Iowa mid-year because your incompetent tax advisor couldn’t understand the tax code outside the NY metro area? More expensive.
Finding out that that metric ton of cash, plus the associated underpayment fees to the fed and every state in the union are also the aforementioned tax advisor’s fault? Infuriating.
Selling all of the shares in a company that made you miserable, near a 52-week high, just after long-term gains set in, in order to make a down payment on said taxes and penalties? Priceless.