Is asking a cab if they go somewhere in a major city normal? Excuse my ignorance if it is, but I'm from a very small town (so no prior experience with cabs in g

Is asking a cab if they go somewhere in a major city normal? Excuse my ignorance if it is, but I'm from a very small town (so no prior experience with cabs in general) and have lived in Chicago (city and suburbs at various times) for the last 5 years and I have never even thought to ask a cab driver if he goes somewhere in particular. And I've taken cabs pretty far within the city. The only time I was ever refused was when I tried to get a ride to the suburbs (a mega expensive cab ride but I needed it).