Eat the Frog
Do the worst task first thing, per the Mark Twain-attributed advice. Productivity culture's breakfast metaphor. The frog is usually an email you've been avoiding for six days.
Heard in the wild
“Eat the frog: call the angry vendor before opening Slack.”
Tone check: Cliché
Genuinely effective habit under the silly name. The dread costs more than the task.