Suaviza tu “no”: es que, No, si… y posponer con buen rollo
Dannis
Es que + reason = softens a “no”. (roughly: “it’s just that…”). Example: —¿Puedes hoy? —Uf, es que tengo entrega.
Meaning: “Can you today?” — “Ugh, it’s just that I have a deadline.”
To postpone: Lo vemos mañana + friendly tone. Example: Hoy voy a tope; lo vemos mañana, ¿vale?
Meaning: “I’m swamped today; we’ll look at it tomorrow, ok?”

No, si… + apparent agreement + objection. It softens disagreement. Example: No, si me encanta el plan, pero ahora no me da la vida.
Meaning: “No, I do love the plan, but right now I really don’t have the time.”
Porque vs es que: Porque = objective cause: No puedo porque tengo reunión. Es que = gentle justification: Es que estoy liado hoy.
Meanings: “I can’t because I have a meeting.” / “It’s just that I’m really busy today.”

Close with así que to make a proposal: Así que lo vemos mañana a primera hora, ¿te parece?
Meaning: “So we’ll look at it first thing tomorrow, what do you think?”
Office culture: you’ll hear “estoy liado” (“I’m swamped/busy”), “la hora del cafelito” (“little coffee time”) to mark the rhythm of the day and to postpone things without tension. Avoiding tasks: escaquearse / procrastinar (to dodge things / to procrastinate).
Pro tip: add a “No te preocupes” (“Don’t worry”) or “Gracias por entenderlo” (“Thanks for understanding”) to sound warmer and more approachable.