Disadvantages of Riding Larger Frame Sized Bike than Reccomended Frame Sized Bike
Actually knowing if a bike frame is the correct size based on height is nearly impossible, they are best guesses. When looking at fitting a bike there are so many different things a fitter will look at.

First lets look at what changes on the bicycle when you change frame size:-


Top Tube (TT) - this is normally measured as a theoretical as this tube is not normally straight, see the below diagram. This determines how far you have to stretch on the frame
Head Tube (HT) -  this determines how long the steerer is, this is how far down the stem could be mounted as a minimum, but also usually means that they can be mounted higher as well, simply the longer this is the higher the bars tend to be.
Seat Tube (ST) - this determines how low you can get your saddle, and how high - the longer the seat tube the higher your saddle can be as a minimum, and the higher as a maximum.




So lets look at what all this means for you. 
If you happen to have short legs and a longer torso/arms, this could mean that a larger frame could be better, as the length of all the tubes increases. To break it down. The top tube length will help as the reach will increase, and usually no one has short enough legs to need seat post all the way into the frame.

If you happen to have very long legs and a short torso, its actually more difficult to size and then fit. This is because you have a short reach, which means you need a smaller frame size, but you need to have all of the seat tube out of the frame, this in conjunction with a short head tube means you will have a larger saddle to bar drop (great for the pros, horrific for those not flexible enough, or used to it!).

Having a frame too small and large also has an effect on handling, a larger frame is more cumbersome but much more forgiving and much less twitchy. A smaller frame the opposite is true, much "flickable" and maneuverable, but with the downside of being twitchy. 

This is before we even get into the micro adjustments like stem length, angle and position; saddle position and angle etc etc. Which all again have an effect on handling and comfort e.g. a long low stem makes the bike feel great at high speed, but like a bus at slow speed.

The key points for you as a rider, are the points of contact with the bike and ensuring they are in the correct position. This will affect the overall comfort of the bike. i.e. while a stretched-out, super-low position might be fast, for a prolonged period it can be uncomfortable. And the converse is also true, an upright comfortable position may suit, but this can be slow.  The aim here is to find the compromise of comfort, speed and handling.


  (I dont have any problems with reaching ground with my feet when I stop)


This is only important in so much as ensuring when standing over the top tube you can put both feet flat on the floor.