Hear the trigger, pick the mood, and mean exactly what you said — out loud.
Mood in Spanish tracks how real something is to you, and the choice changes the meaning, not just the form. A known, specific thing takes indicative — conozco a alguien que habla alemán — but a sought or hypothetical one takes subjunctive: busco un empleado que hable alemán. Time clauses split the same way: pending future actions go subjunctive (cuando llegues, avísame), while para que and antes de que always take it (te lo explico para que lo entiendas). Some verbs even change meaning with the mood: siento que tienes razón = I sense you're right, but siento que tengas que irte = I'm sorry you have to leave.
Below: the clause types and minimal pairs that decide the mood, the traps that catch even advanced learners — and a way to make the choice at speaking speed, no drills, no worksheets.
Say this
Regional Spanish
Textbooks teach one word. Locals use several — pick your region's and stay consistent.
Watch out
The part no drill site can do
Carla
Your grammar teacher for this pack
There's nothing to fill in here — in the Mood Swinger lessons you talk, and Carla makes you choose the mood live, where it actually matters. She gives you one noun and two situations: someone you know (conozco a alguien que habla...) and someone you're hunting for (busco a alguien que hable...). She flips cuando llego against cuando llegue — habit versus plan — until you feel the difference instead of computing it. Then she runs the doubt hierarchy: say creo que tiene razón, no creo que tenga razón, and creo que no tiene razón, and rank how sure each one sounds. Out loud, in a real exchange, until the mood chooses itself.
Blank mid-sentence and nothing bad happens — she waits. That's the practice, without unnecessary judgement.
Quick answers
Both are correct, but they carry different weight. No creo que sea buena idea (subjunctive) doubts the whole proposition; creo que no es buena idea (indicative) positively asserts the negative. And no dudo que vendrá takes indicative, because removing the doubt restores certainty.
Only for pending, future actions: cuando llegues, avísame — when you arrive (someday), let me know. Habitual or past events take the indicative. The same rule covers en cuanto: en cuanto termine, te llamo.
Yes — purpose clauses with para que take subjunctive with no exceptions: te lo explico para que lo entiendas. So do antes de que and sin que. Concessions like aunque llueva, saldremos take it when the outcome is still open.
It's the known-versus-unknown antecedent rule. If the person or thing is real and specific, the relative clause takes indicative (tengo una casa que tiene jardín); if it's sought, hypothetical, or nonexistent, it takes subjunctive (quiero una casa que tenga jardín, no hay nadie que pueda ayudarme).
Sentir que + indicative = to sense or perceive (siento que tienes razón); + subjunctive = to regret (siento que tengas que irte). Entender que works the same way: entiendo que no quieres venir reports a fact, entiendo que no quieras venir accepts a feeling.