Serve with joy, not sadness

In the same passage the Arizal warns that a person may not stand before Hashem in sadness. He should serve like a servant who is happy to serve his master, because a sad soul lacks the strength to receive the higher light drawn down through prayer. The place for brokenness is during viduy and when recalling one's sins; for the rest of davening, even worries about past sins should be set aside.