@show-Zi because you created your own annoyances probably by doing a lot of admin tasks or using tools requiring (legitimately or not) admin privileges.
For example some softs on SUA doesn't requires admin rights when executed, while in admin account, they do.
Remember, UAC is there to restrict auto-elevation (common behavior of many malware) hence execution of process having significant impact on the system.
Admin account is supposed to be used for admin tasks only, not daily use. When using Admin Account, you run in high privileges session which gives any potential malware less difficulties to compromise your system.
I use SUA as my daily account, and unless I run some specific Windows admin tools or programs (backup softs., etc...) I don't get any UAC prompts.
People are too used to use admin accounts even some devs, because in the past MS making the default user account as admin account.