bane of someone's existence

a boon and a bane

Something that is both a benefit and an affliction.

another nail in someone's coffin

An event that increases the likelihood of or causes further failure.

answer someone's prayers

To be or do exactly what someone has been wishing or asking for.

answer to someone's prayers

Exactly what someone has been wishing or asking for.

apple of someone's eye

The object of somebody's affections; a person (or sometimes a thing) that someone strongly prefers; a favorite, a loved one.

bash someone's face in

To beat someone violently.

bash someone's head

To beat up someone violently.

be someone's to lose

To be anticipated to be won by someone.