Counting cards in real life doesnt really work. It can tilt the odds in your favour but works on the principles of previous cards played and a limited number remaining that favours either high or low cards. If you know more low or high cards remain, you know there is a higher chance of getting higher or lower cards if you decide to hit.
In casinos often they shuffle regularly to prevent the cards reaching a predictable set. Card counting as you know, is the method of which you can estimate the remaining value of the cards that havnt been played and due to regular shuffling, the chances for a deck reaching a point where odds have tilted enough in your favour to make decent predictions make card counting time consuming and boring. You can even sit infront of a dealer all evening and find that no deck has tilted to a predictable extreme limit (where mostly low or high cards remain). Famous card counting stories almost always involve a group of people, so you can have them all counting cards at many different tables at the same time to see if any decks become reliable and of course there was no doubt some strong measure of luck assisting the exaggerated wins of these people.
When i studied physics, our maths lecturer set upon us the task of learning more complex card counting strategies and then applying them to much more obscure situations (where a certain number of cards are known to have been drawn and the games were normally different, games where card counting gives you a near negligible advantage) then we had to work out probabilities of pulling out certain cards/suits and hands (when this was applied to poker). This was all a way to keep us to speed with simple mathematics in long winded questions and also to give us a perspective in probabilities in real life situations when the number of unknowns are quite high. What a waste of time this was.