Is it a good idea to build a tall cabinet next to the refrigerator?

It can work, but it depends on how you use it. A tall cabinet next to the refrigerator has the advantage of letting the refrigerator sit flush within the cabinetry for a tidy look, and the space above can store items you don't use often. Keep two things in mind: first, leave a gap for refrigerator heat dissipation—don't press it tight against the cabinet body, and for built-in refrigerators in particular, follow the manual for ventilation clearance; second, don't make the tall cabinet much deeper than the refrigerator, or opening the door and reaching for things will feel awkward. During measuring, we check wall flatness and internal and external corners, then decide the finishing method to avoid large gaps between the cabinet body and the wall. You can also visit the factory to see processes such as cutting and edge banding, which gives you more confidence.