What was the biggest mistake candidates often do when trying to get into buy-side roles?

For peeps who's already working in PE, HF, VC, AM, or family offices, what do you think is the biggest mistake people make when they're trying to get their foot in the door?

I'm especially curious about the things that aren't obvious from various job descriptions or standard interview guides. For instance;

- Over-focusing on their credentials and still underdeveloping actual investing knowledge

- Having a resume that looks good but doesn't show clear investment thinking

- Not knowing how to discuss an investment thesis during interviews

- Applying to firms without understanding their strategy or investment style

- Being technically prepared but struggling with behavioral or fit questions

For people who experienced interviewing candidates, what immediately made you think "this person could succeed?" and what are the red flags that make you pass?

Would also be interested in hearing how this differs between PE, HF, VC, and asset management.