Probably repeating words in the same sentence and being too wordy.
I agree with this wholeheartedly, and it's always made me lowkey self-conscious as a writer that I'm the only person I know who does this. ^^;
Like, I use a lot of ellipses and 'um' and 'oh' and 'like' all the time, because...I mean, that's how normal people tend to sound when they talk. For everyone in a book to "Say exactly what they mean in clear efficient words. Period." is really weird and immersion-breaking to me...it's a constant reminder that I am, in fact, Reading a Novel, instead of simply experiencing a story.
And I kinda think maybe a lot of writers would struggle less with dialogue if they allowed themselves to let characters sound like people, instead of always saying something "quotation-worthy". There's a time and a place for the zingers and the poetry; when you make characters talk like that all the time they just sound artificial.
Anyway, my own biggest writing flaw is (fittingly) making characters talk too much. ^^; I love dialogue; I love to just sit and watch characters converse in my head and write everything down. I don't even mind large group discussions, especially when the characters know each other fairly well and everything flows naturally.
Unfortunately, the longer I go on letting them talk, the further they tend to go off topic. ⚆u⚆; Every time I set up a long conversational scene, I look forward to it, but the work of constructing it is usually weeks of revising and re-revising to get rid of cute, fun lines that don't actually make sense, or deliver the wrong message about the character, or take the convo in the wrong direction, etc.
And it's very painful...to the point where sometimes I weaken and just leave in a line I really like even if it's not particularly "right" for the scene. It's fine...no one will know......
Whaaaa, is that true?? I feel like it would explain a lot about why I enjoy his TV writing so much. ^^
Tbh I find myself doing the same thing with my voice actors...more and more often I imagine their voices when I write instead of the "anime dub" voices I usually use, and tailor their lines accordingly~
Yeah! I heard it on a documentary or a video commentary about the Dick Van Dyke show. The actors were all pros so he trusted a lot of their choices. I remember that the actor who played Buddy had a very particular way of speaking so he learned how to write to how the actor spoke.
Even if you didn't know his writing style, if you listen, all of the dialogue sounds "normal". Like you could easily perform the script in the 21st century and not tell the difference. Compared to other shows of the era, they sound very... theatrical? They sound very staged and phony
One of my biggest writing flaws in writing is advancing the plot. I pour way too much on chapter 1 and it left me on a massive writer's block.
I hate keeping scenes up because whenever I see them a day or an hour later it feels cringeworthy to me, so I delete it or edit it.. I don't really get a lot of stories done because of this. I guess I'm also not that good at writing more grounded stories, too.
I am WAAY too verbose on the sentence level (and less so on a paragraph level). Like, I don't think it's terrible per se, but my scenes go on for just a little too long with just a little too much detail. I think I can definitely shrink my writing to about 60-70% of its current length and keep the same content (character/world-building and plot) in a much more succinct package.
Being repetitive has happened to me a lot and the other thing is that sometimes I overlook important details of a certain scene. 
Being unclear: I've gotten this feedback since my school essay writing days but somethings that I think are clear as day are apparently unclear from the reader's POV.
Talking scenes drag on in one stationary scenery: I've been trying to be better about this ever since I watched a youtube video addressing this sort of writing issue but sometimes when I'm pressed for time and/or are tired, I do fall back to it.
Too many sentences (in the draft at least) are long, complex monsters that need to be cut down to size.
What’s Your Writing Flaw?
My scripts are so fire the smoke detector keeps going off and waking everyone up.
For mine I think is the flow of a story and how good the reader can understand!
If I could draw I would surely do comics because I like reading them and I like the story-telling of comics but since I'm untalented I ended up writing light-novels
Sometimes I feel like I can't deliver a scene I imagine in my head the way I want and probably ruin the scene and for other times I don't know how to smoothly change the scene, I have been writing for a year now and I can tell my skill has greatly improved from the start but I can still see the flaws and always trying to get better
I have dyslexia, so maybe common grammar errors that I sometimes don’t spot. My professors also told me my writing was too “casual”, which might not be too much of a problem if I am writing dialogue.
For plotting, I got somewhat inspired by the film Vertigo. So I do sort of having these stories that sort of make your head spin. I had a writing professor say that some countries teach to write research papers like a spiral where you only learn what the point is at the end. So maybe my flaw is liking this style of writing.
I'm just unable to write novels in general :T
I wanna get into novel writing but like... I dunno if I'll ever be able to pull it off.
I cannot for the life of me, describe anything or I overdo sentences with extra words 
I know I stopped writing for a couple of years but when I came back to it I realized that my writing is prose like, no descriptions of where my characters are or even what they look like. And then when I go back and read it Im like UHHHH I don't think the reader will read your mind and know that the character is supposed to be sitting down with a pen between his fingers in an office lmao.
