Idioms describing people

Positive and negative qualities
She has a heart of gold.
[очень добрая, щедрая; золотое сердце]
He is as good as gold.
[щедрый; хорошо воспитанный, обычно используется в разговоре о детях; золотой ребенок]

Negative (-)
She's as hard as nails.
[никакого сочувствия к другим]
He's rather a coldfish.
[отдаленный; недружелюбный]

He's such an awkward customer.
[сложный человек; человек с тяжелым характером]
She's a pain in the neck/ass. Nobody likes her.
[божье наказание]
He gets on everyone's nerves.
[играет у всех на нервах]

People's 'fast' and 'slow' qualities
He's very quick off the mark (действовать незамедлительно); he always gets things before everybody else.
You've asked him to marry you! You're a fast worker (шустрый)! You only met him three weeks ago!

I was a bit slow off the mark (мешкать;медлить); the job had been filled by the time I got the forms.
Come on! Hurry up! You're such a slow-coach/ slow poke (копуша)!

How people relate to the social norm
She's a bit of an odd-ball; very strange. [своеобразный; странный]
He's really over the top. [очень завышена самооценка]
He's round the bend, if you ask me. [абсолютно сумасшедший / ненормальный]
My politics are very middle-of-the-road. [очень правильно: ни «правых», ни «левых» наклонностей]