(informal) to shoot oneself, to blow one's brains out

(informal) to tie oneself in knots, to worry oneself sick

(informal, figuratively) to rack one's brain, to cudgel one's brain

(informal, figuratively) to rack one's brain, to cudgel one's brain

(figuratively, informal) to rack one's brain, to cudgel one's brain, to put one's thinking cap on

(informal) to feel exhilarated; to be beside oneself with pride, to feel very proud (to the point of arrogance and haughtiness)

(informal) to do a bunk, to take French leave, to skip town, to show a clean pair of heels

(informal) to do a bunk, to take French leave, to skip town, to show a clean pair of heels

(informal) to imagine things, to have another think coming, to be deluded

(vulgar) to get lost, to go to hell, to go fuck oneself