A word that means 'hateful but indispensable'

Is there a single adjective meaning 'hateful but indispensable' or something close? (Not "love-hate"). British or American would be OK.

Solution 1:

Necessary evil comes to mind first.

a necessary evil something that you do not like but which you know must exist or happen He considers taxes a necessary evil. See also: evil, necessary Cambridge Idioms Dictionary, 2nd ed. Copyright © Cambridge University Press 2006. Reproduced with permission. retrieved online on May 22, 2014 at http://idioms.thefreedictionary.com/a+necessary+evil

Solution 2:

I've noticed that the adjective lovable is often used to describe people or pets who elicit ambivalent feelings:

He was the bon vivant of The Boar’s Head Tavern and the philosopher of Eastcheap – a lovable rogue who not only made us laugh at him and with him, but also at ourselves [On Shakespeare's character Jack Falstaff]

GameDaily commented that while he is a "lovable oaf," others may see him as a "fat Pacific Islander who loves stuffing his face" [Description of Nintendo / cartoon character King Hippo]

I don't know how he does it but he is a lovable serial killer. [On the merits of Michael C Hall's acting performance as Dexter]