"Por Qué Me Ilusionaste" is Remmy Valenzuela asking the question every heartbroken person asks: why did you let me get my hopes up? The verb in the title, ilusionar, is a lovely one to learn. It doesn't mean "to trick" but "to fill someone with hope or excitement," so the title means "Why did you get my hopes up?" He starts by facing the truth: "Me di cuenta que nunca tuve tus besos" (I realised I never had your kisses) and "Y yo para ti, fui solo un pasatiempo" (and to you, I was only a pastime). Me di cuenta (I realised) repeats line after line, like he's counting every lesson.
The chorus lists what fooled him: "esas tiernas caricias" (those tender caresses) and "aquellos bellos detalles que pintaban mi sonrisa" (those lovely little gestures that painted my smile). Detalles here means the small thoughtful things a partner does. Then the hurt question: "¿Por qué fuiste tan cruel de demostrarme algo que tú no sentías?" (Why were you so cruel as to show me something you didn't feel?). His answer is to shut down completely: "Desde hoy cierro yo las puertas al amor" (from today I'm closing the doors on love). Dramatic? Absolutely, and that's exactly what makes it fun to sing.