one of the things that happens allot when you are designing a game is asking yourself what if. Let me give you a hypothetical that I encountered just today.

I have an issue of quest Items.

every now and again, the player will have to talk to an NPC (Non Playable Character) and as a result of that interaction will be given an item which is prudent to the story in one way or another. This is all well and good and actually quite standart, but wait, there is a problem: Say the player has already filled up his/her inventory, but this interaction forces the game to add another thing to the inventory of the player, what happens then?

adding additional items to the inventory could potentially break the game, as the gameobject most likely would get lost, making the player unable to complete the game and breaking the entire game.

I could have the NPC ask the player character whether he/she wants to add another piece of content to the inventory, which he she would not be allowed, if the inventory is full.

I could have the item drop at the feed of the character, to be picked up when the player has the time to make space in his inventory.

I could make the game delete a random piece of inventory to make space for this new item, leaving the player with no say in the matter.

the really great thing about this problem is that it is highly hypothetical. I have not yet seen this problem in action, but I know that it could happen at some point during a play through. this sort of pre-emptive problem solving is quite normal for my kind of game development and it is one of the biggest things that hold back development.