Paida and ludus

Paida and ludus as I understand it are two different game play types.

Paida is where you play the game just for fun, there is no outcome or goal to achieve but you get a lot of fun out of the game by doing something.
Ludus is where you play a game to achieve a goal, this could be to beat a boss, get to the end level or to achieve goals and complete missions.

There are a few games where both are included, a good example is Grand Theft Auto games, you can choose to finish missions to achieve reputation, become stronger and unlock new areas or you can choose to just run around shooting at everything in site, drive/fly around or just free-roam around the map in any way you like.

There are also games that consist of ludus mainly, a good example of this would be poker. When people play poker seriously they play for a lot of money and therefore will want to win, for this reason it becomes mainly a ludus game even though fun can be had from the game. Although, poker can also be played as mainly a paida game, it can be played between friends with no money involved, when this happens they are just playing for fun. They do want to win but do not become worried about loosing as it is just friendly.

There are very few games that consist of one type or the other, If a game was made without paida in mind then it would be hard to have any fun on the game and would get very frustrating constantly aiming for a goal. However, it is much easier to make a fun game when the player must complete a goal, without a goal the player gets bored and can run out of things to do after a while. In my opinion there should be no game that exists without one or the other as it would make the game less interesting and people play games for fun.