Confound it/you!
Definition 1 of 2
Pro Tip 1/3Emotional Intensity
The phrase adds strong emotion, often without genuine anger. 
Confound it! That’s the third time this week.
Pro Tip 2/3Archaic Mildness
Considered old-fashioned and milder than modern swear words. 
Oh, confound it! I missed the bus again.
Pro Tip 3/3Humorous Temper
Sometimes used humorously to mock frustration. 
Confound it, where have those elves hidden my shoes?