A
World building
I create interesting and consistent worlds with ease. I am able to start with a few ideas, make them into a setting for a one-shot in an evening and for a campaign in less than a week. When I run a game, the setting (its geography, history, important NPCs and power structures, religions and cultures etc.) plays an important role in the plot. This king of exploration is something I like and what my players really enjoy.
B
Improvisation
I nearly never prepare detailed plots, I let my players control where the game goes. It is not a typical "sandbox", with world being passive until the PCs show up. The world lives by itself and it reacts to everything the PCs do. For this reason, I, generally, don't plan "what will happen". I have places and NPCs with their methods and motivations and I improvise events during a gaming session based on my players' decisions.
It is B, not A, because it happens sometimes that I understand in-game situations differently than my players and either hit them with consequences they feel they couldn't predict or develop a subplot they got the hook for, but aren't really interested in.
Descriptions
I have very good visual imagination and I may make up fascinating descriptions on the fly, creating the mood I need. It goes for places, characters, items and action scenes. I can fit the descriptions to current situation, flavor them for each character's perception tendencies. Reading pre-generated descriptions in adventures is something I never even considered.
It is B, not A, because sometimes the descriptions (especially the more climatic ones) suggest aspects of in-game situation different than what I mean and in games where players have little narrative control it may cause problems.
C
NPCs
While I can create interesting and multi-dimensional NPCs, not always I'm able to play them to the full. I need to "feel" a character, to immerse like a player, to be able to roleplay everything I intended. If I need to create an NPC on the fly and don't come up with some catchy quirks, or if the situation calls for too many NPCs roleplayed in a short time, some of them become flat or are completely forgotten.
On the other hand, some NPCs I create are really good and are remembered by my platers even years after they met them in game. Some of them players like, some they hate, but they remembered best the ones who they cannot decide if they love of hate.
D
Communication
I quite often misunderstand my players or fail to see problems brewing up. I have nearly no empathy and don't know what people think and feel unless they speak it up. A few times I didn't see an issue in game until it was big enough to threaten the campaign.
For some time, I have tried talking with my players after game sessions to find out what they like and what they don't and it helps a lot, but I still can't call my skills in this aspect good.
F
Plot
No matter how I try, I cannot create a plot that my players would follow. After no more than a few hours, I'm faced with a choice between railroading them and getting out of tracks myself - so I give up, let the players take over the plot and fall back to my default, reactive and improvisational, mode of GMing. I focus too much on keeping the world consistent and alive to be able to keep players to a single direction.
World building
I create interesting and consistent worlds with ease. I am able to start with a few ideas, make them into a setting for a one-shot in an evening and for a campaign in less than a week. When I run a game, the setting (its geography, history, important NPCs and power structures, religions and cultures etc.) plays an important role in the plot. This king of exploration is something I like and what my players really enjoy.
B
Improvisation
I nearly never prepare detailed plots, I let my players control where the game goes. It is not a typical "sandbox", with world being passive until the PCs show up. The world lives by itself and it reacts to everything the PCs do. For this reason, I, generally, don't plan "what will happen". I have places and NPCs with their methods and motivations and I improvise events during a gaming session based on my players' decisions.
It is B, not A, because it happens sometimes that I understand in-game situations differently than my players and either hit them with consequences they feel they couldn't predict or develop a subplot they got the hook for, but aren't really interested in.
Descriptions
I have very good visual imagination and I may make up fascinating descriptions on the fly, creating the mood I need. It goes for places, characters, items and action scenes. I can fit the descriptions to current situation, flavor them for each character's perception tendencies. Reading pre-generated descriptions in adventures is something I never even considered.
It is B, not A, because sometimes the descriptions (especially the more climatic ones) suggest aspects of in-game situation different than what I mean and in games where players have little narrative control it may cause problems.
C
NPCs
While I can create interesting and multi-dimensional NPCs, not always I'm able to play them to the full. I need to "feel" a character, to immerse like a player, to be able to roleplay everything I intended. If I need to create an NPC on the fly and don't come up with some catchy quirks, or if the situation calls for too many NPCs roleplayed in a short time, some of them become flat or are completely forgotten.
On the other hand, some NPCs I create are really good and are remembered by my platers even years after they met them in game. Some of them players like, some they hate, but they remembered best the ones who they cannot decide if they love of hate.

D
Communication
I quite often misunderstand my players or fail to see problems brewing up. I have nearly no empathy and don't know what people think and feel unless they speak it up. A few times I didn't see an issue in game until it was big enough to threaten the campaign.
For some time, I have tried talking with my players after game sessions to find out what they like and what they don't and it helps a lot, but I still can't call my skills in this aspect good.
F
Plot
No matter how I try, I cannot create a plot that my players would follow. After no more than a few hours, I'm faced with a choice between railroading them and getting out of tracks myself - so I give up, let the players take over the plot and fall back to my default, reactive and improvisational, mode of GMing. I focus too much on keeping the world consistent and alive to be able to keep players to a single direction.