LC circuit in radio receiver
The L-C filter used to tune to particular radio stations has high Q.  Put another way, it passes only a narrow notch of frequencies.  When the notch-pass filter is tuned to a particular frequency, it will pass that frequency but heavily attenuate others.  Radio stations are spaced far enough apart in frequency so that the signals for other than the desired station are attenuated to below the "don't care" level.