Chess excellence depends very much on experience: the more you play and train, the better you get. See, people say it's the mind game, but it only depends on the intelect as long both players are similarly experienced.
Also, a game of chess is long and can get boring: in the beginning of a game people usually play "by the book", trying to adhere to some basic principles (control the center of the table, pull out your pieces into play, protect your king by castling, etc).
In the middle of the game, as long as you managed to avoid losing any piece so far, is where the actual play takes place, when you try to gain material advantage and this is where I spend most of my thinking fuel.
The end of the game, again, depends very much on training and experience, because there are known strategies how one should play with pawn and king against king for example. Of course, some of the strategies are obvious, like promoting your pawn to a queen and mate your opponent, but others are not, like gaining the opposition to be able to promote/block the pawn.
I don't have too much patience playing whole games myself, but I like training my mind by making chess puzzles/tactics daily, which I'd recommend you try yourself: your offered a position where you know that after a few moves you have to end up in advantage.