要V就V【yào V jiù V】

要 + verb + 就 + the same verb says: if this is going to happen at all, let it happen fully. The second verb usually carries something extra that says how – properly, the good one, early, to the end. It's spoken.

With 吧: go ahead

When the second verb ends with 吧 and nothing else, it gives permission: if you want to, do it, it's up to you.

想V就V says "do it whenever you feel like it", and V就V on its own shrugs a thing off; both are separate patterns.

Subject first, same verb twice

The subject goes before 要, and the two verbs are the same word.

• × 要你去就去 → 你要去就去
• × 要学习就学 → 要学就好好学