Two days ago, I took the example of vegan as a label to talk about how merging such labels with our own identities makes decision making far easier and consistent and automated. 

But there are cases where this is a useful and beneficial tactic and there are cases where this can go horribly wrong. 

And what makes the difference is two things. 

Firstly, the objectiveness of the definition of the label. 'Vegan' has a very objective definition. You either are a vegan and never eat meat and dairy or you're not a vegan and eat them. Some labels don't have such an objective definition. 

Secondly, the pervasiveness of the definition. 'Vegan' means the same thing no matter who you ask. Although the label of 'Vegetarian' has that problem. Some people consider egg as vegetarian while some don't. Such differences can easily get out of hand when the terms are more loaded like 'Socialist' or 'Religious'. 

The first kind of labels are good while the second can lead to a lot of misunderstanding and can be used for manipulation, as happens during elections.