I had never noticed this until last autumn when my I started teaching my daughter to drive and took her to a local airfield in the TF, she found it difficult to get the revs right - either to little or to much revs, I tried to replicate what she was doing and then discovered that the throttle pedal was a bit sticky and it was difficult to apply more revs slowly.
Now that the car is back on the road again, I have been more aware of it, partly due to a current problem I have with my right leg/foot so decided to investigate
I found so much slack in the throttle cable where it connects to the throttle flap on the engine air intake, it was a simple job to adjust out the slack and then out for a test drive, what a difference - the revs are now easy to control, wish I had done it months ago