In the complex world of browser cookies, issues often arise when settings don't persist or cookies aren't included in requests, largely due to size limitations, domain mismatches, and attribute misconfigurations. For instance, cookies exceeding 4KB are rejected, and incorrect domain attributes can prevent cookies from being set. Debugging typically involves using browser DevTools to inspect request headers and error messages. Common issues include the misapplication of cookie attributes such as Secure, HttpOnly, and SameSite, with each having specific requirements for successful deployment. Cross-domain requests can complicate cookie behavior due to privacy protections, especially when cookies are not sent because of restrictive SameSite settings or missing credentials in fetch requests. The guide emphasizes the importance of understanding browser settings and attributes for effective cookie management, while advising caution with third-party cookies due to potential privacy violations.