How fast is the PIC?
Let's put things in perspective here. We humans can't distiguish events faster than probably 10msecs. That is, if I press a button, and if the controller responds even after 10 msecs later, we would think that the response was still immediate.
Using a 4Mhz crystal, in 10 msecs, a PIC would have executed more 10,000 instructions. That is more than the program space of a PIC16F84 chip. You would have gone through several loops of your program and still would perceive the response of the PIC as immediate.