If you've ever watched a stock you were about to purchase leap in value in a short amount of time, keeping you sidelined, I feel for you, earnest investor. OK, to be honest, I feel for myself every time this happens.McDonald's Corporation (NYSE: MCD) well illustrates this phenomenon. After a quick 30%-plus total return in 2015, the company is pricier today than it has been in several years, complicating a current "buy" decision.Its trailing-12-month price to earnings (P/E) ratio, which floated around 17 in the three years preceding 2015, now sits above 23.