Jira sends an email alert with a subject containing "Assigned" in two different situations:

a. When I assign an issue to someone
b. When someone assigns an issue to me

The situation b is much more important to notice, but with the current setup I can't filter the message in my email client.

Maybe every message that is an alert of a change I've done myself should have other kind of a subject line so I could mark them read in my client automatically.