K7 is absolutely right. For example I picked #18 @ Congressional, a great Par 4 finishing hole. The Yellow Tee's (TM) are 466 yds, the Black Tees (L and above) are 520 yds.
It will probably be most obvious on the Par 4's, but I imagine some Par 3's will show some difference also. Just enjoy it as it's a whole new game. Many approach shots will be long irons, or even a 3W when playing into the wind.