blacklisting specific email addresses
The ability to prevent specific email addresses from being logged in the CRM is super-important. I am genuinely surprised this isn't already a feature.
Asking users to remember to toggle the track email on/off isn't a viable solution - it's anti-productivity (not great for a CRM). It means confidential information is liable to be viewed by people who shouldn't have access inside a business and imporant sales/customer information may not get tracked because the individual forgot to keep ticking a box on and off.
The toggle option is barely tolerable for teams only doing 1 function (sales for example) but anyone of manager level or anyway working between multiple functions will suffer from this lack of (pretty basic) functionality.