Here’s a real-world warning: the Eventim Apollo is old, and old buildings have pillars. Some seats are marked “Restricted View”, and they mean it.
You might get a pillar blocking half the stage. Imagine trying to watch a football game through a lamppost. Frustrating. Avoid these unless you’re a fan of “audio-only” experiences.
If a ticket is suspiciously cheap, check the seat number on a fan forum. You’ll thank me later when you’re not craning your neck around a column.