If you've never been there... then just go. The place is amazing. And so is Barcelona as a whole. I've visited the Sagrada Familia back in 2000, when they were still building slowly and expected it to never be ready. I returned 20 years later, with my twenty-ish daughters, and found out the local government had a change of plans and mostly finished it.
No matter if you think the (sped up) build does Gaudi any justice, the place is still amazing. Just enter that cathedral and stand in awe.
(Click to enlarge.)