I love VFX. I dont love noticing it though. If I notice a VFX as one, it usually means it was poorly executed and therefore looks fake.
Set Designers are often asked to draw the lower half or portion of a set, which VFX will later add an extension to in Post. There is often a huge disconnect between Art & Post, often its a vast canyon of non communication.
Have you ever watched a show that looked like so much money went into it but all the VFX were terrible? Often there is an overload of work that wasn't budgeted for that ends up being dumped on the VFX dept after everyone's all gone home and the mony's spent. This is why often the VFX end up crappy.
Good communication at the set design level between the departments is key to a happy ending in Post.
If you know the set will have an extension, you can help the VFX artists by designing the set with a deliberate cutter line at the extension line, like a cornice, or a conduit, or a brick pattern etc.