What Code Should Be in UObject Constructors?

I have been using a lot of UOject classes in my project. Some of them I have found myself not adding any code into the constructor because it doesn’t seem to need any. I know that the class requires a constructor for it to work but apparently there doesn’t need to be code inside for it to compile and for it to run correctly.

What I am wondering is, is this something I should pay attention to? Is it bad coding to not put any code into the constructor?