Before a player joins a "hosted game", they are shown all information including the opponent's game completion rate, dictionary setting, expected rating change and opponent information. Hence joining a game and deleting it immediately is unfair to the opponent (they need to place another request for no fault of theirs).
A player's GCR reduces each time they delete a game that they have joined from a hosted table. If the GCR falls below a specific level, the player is prevented from joining additional hosted games. The player can continue to post requests or play with friends.
How to maintain a healthy GCR?
Make sure you try to finish every game you have started playing and do not delete games without a proper reason.
How to improve your GCR?
You need to complete more games (either with friends or via hosted game requests of your own) and your GCR will keep rising.
Additionally, you can also consider the following tips to improve your GCR:
Play with opponents who have a similar skill level to yours. This will increase the likelihood of you winning games, and thus improving your completion rate.
Take breaks between games. Playing continuously for long periods of time can lead to fatigue, which may cause you to make mistakes and lose games. Taking breaks will help you maintain your focus and perform better.
Review the games you've played. Analyzing your past games can help you identify areas where you can improve your gameplay. This can help you avoid making similar mistakes in future games and increase your chances of winning.
Communicate with your opponent. If you need to leave a game due to an emergency, let your opponent know. This can help them avoid waiting unnecessarily for you to return to the game and also reduce the chances of them reporting you for leaving the game abruptly.
Practice good sportsmanship. Even if you lose a game, try to remain gracious and respectful towards your opponent. This can help you maintain a positive reputation among other players, and encourage them to continue playing with you.
To add to the previous response, there are some additional tips that can help you improve your gaming completion rate (GCR). Firstly, it's important to play against opponents who have a similar skill level to yours. This will increase the likelihood of you winning games and, in turn, improve your GCR.
Secondly, taking breaks between games is important to avoid fatigue, which can lead to mistakes and lost games. Taking a break will give you time to recharge, maintain your focus, and perform better.
Thirdly, reviewing past games is an effective way to identify areas where you can improve your gameplay. This analysis can help you avoid making similar mistakes in future games, and ultimately increase your chances of winning.
Additionally, it's important to communicate with your opponent if you need to leave a game due to an emergency. Letting them know can help them avoid unnecessary waiting and reduce the likelihood of them reporting you for leaving the game abruptly.