What is the most frustrating thing about guest posting for you?

Like the title says, I would be curious to know, what is the ONE thing that frustrates you most about guest posting, whether it is done through manual outreach, or buying guest posts from agencies or platforms? Some examples: Finding opportunities? Selecting guest post sites? Lack of transparency? Too expensive? Too time consuming? Low response rates? Avoiding PBNS? Guest Post Farms? Writing articles? Anything else?