¡Y además te quejas!

And still, you're complaining!

Caption 7, Tu Rock es Votar - Comercial de TV

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BANNER PLACEHOLDER

Quejarse is a verb meaning "to complain," so we translate the above phrase directed at Mexico's voters as:
"And still you're complaining!"

Así que no puedo quejarme.

So I can't complain.

Caption 33, Federico Kauffman Doig - Arqueólogo

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Similarly, the affable Federico Kauffman Doig uses quejarme when he states "So I can't complain."

On a related note, you won't be surprised to learn, if you didn't yet know it; una queja is "a complaint."

Tengo que pedir el libro de reclamaciones y poner una queja.

I have to ask for the complaint log and make a complaint.

Caption 6, Raquel - El libro de reclamaciones

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Mañana misma pongo la queja.

Tomorrow I'll put in the complaint.

Caption 23, Confidencial: El rey de la estafa - Capítulo 2

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Cuando hace humedad, podemos escuchar a la gente quejándose por ello.

When it's humid, we can hear people complaining about it.

Captions 27-28, Clara explica - El tiempo

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The preposition following quejarse is often de.

Se queja de un dolor en el abdomen.
She complains of pain in the abdomen.

Se la pasa quejándose de que no tiene dinero.
She is always complaining about having no money.