Some class features or feats give benefits that have a limit on the number of times they can be used without resting. I'm all but certain there are more, but I can only find one offhand. The bard's College of Satire says, in part:
At 6th level, you can cast detect thoughts up to a number of times equal to your Charisma modifier. You regain any expended uses of this ability after completing a long rest.
If a creature resists your attempt to probe deeper and succeeds at its saving throw against your detect thoughts, it immediately suffers an embarrassing social gaffe. It might loudly pass gas, unleash a thunderous burp, trip and fall, or be compelled to tell a tasteless joke.
Detect thoughts is also on the bard spell list. If a satire bard of level 6 or higher also knows detect thoughts as a normal spell, does their casting of the spell "normally" have the same effect as the class feature? If so, how many times would the extra effect happen? Can they choose whether the extra effect happens? Does it matter whether they learned the spell before reaching level 6?
For example, could I walk down the street making everyone tell crude jokes while tripping over each other and farting like they're in a remake of Blazing Saddles? Or, if I have a charisma modifier of +3, could I only do it to the first three people I meet each day?