A capital lease is more akin to purchasing the property outright. In other words a capital lease is similar to a purchase of the property. GAAP requires that a portion of the capital lease payments be treated as interest expense. The amortization of the monthly payments is similar to those for mortgage on your home. When you look at a balance sheet, the capitalized lease obligation represents the amount of interest that will be paid over the remaining life of the lease.
Preferred stock is listed under equity, but it's more like debt.
Sometimes if you read the footnotes of a company's financial statements, you'll find that the preferred stock has a mandatory redemption feature that requires a company to pay the holders a fixed amount on a predetermined date. Such stock should be treated as debt. According to the footnotes to Microsoft's financial statements , this preferred stock is convertible into common stock, and the principal is protected. Preferred stock actually pays dividends rather than interest to its holders, but these dividends are normally different than the kind paid on common stock. When the characteristics of the preferred stock require the payment of dividends, we treat it as debt.