We’ve recently installed some new plugins on the Tavern and one of them generates an admin notice that can not be dismissed without disabling it. Not only is this frustrating, but it makes it less likely that I’ll give the developer money to purchase the pro version.
Here’s what the admin notice looks like. I’ve hidden the name of the advertised plugin as the goal is to inform people, not shame plugin authors.

While I expect admin notices when activating a plugin or after a major update, I don’t appreciate the inability to dismiss them. I also don’t appreciate admin notices that reappear no matter how many times I click the dismiss button. The worst part about the notice above is that it shows up on every page hijacking important screen real-estate in the WordPress backend resulting in a terrible user experience.
WordPress plugin authors, I respectfully request that you use the admin notice feature in WordPress for providing crucial information about your plugins and not as a billboard. Give users the opportunity to dismiss them and make sure that when dismissed, they don’t reappear unless the user clears their browser’s cookies.
Turning users’ admin interfaces into billboards for Plugins and Themes is one of my biggest pet peeves. Sadly, in my experience, some of the biggest/best-known/most-used Plugins/Developers are among the biggest offenders.
(Themes, not so much anymore. The Theme Review Team works with Theme developers to find a good balance of upsell promotion and respecting users’ Admin UI, for Themes hosted in the official directory.)