Coca-Cola stock may leave a bitter taste in the mouths of investors.Coca-Cola (KO -0.52%) stock is not a buy.Indeed, such advice may seem counterintuitive at best and nonsensical at worst. The stock has delivered considerable returns for investors since it went public back in 1919. Also, few companies can match its track record of annual dividend increases, which now spans 63 years.Nonetheless, although Coca-Cola stock may look like an appealing buy on the surface, a closer inspection of the stock highlight ...