stray capacitance

Well, this question is quite interesting because of the word ''desirable''.

Actually, stray capacitance usually appears when conducting experiment related with study of capacitance. The apparatus we use is always metal plates which has large surface area and that is also the reason why the capacitance we find in our experiment is usually different from the the theoretical value. Therefore, for experimental purpose, stray capacitance is not desirable.

In fact, the capacitor we can contact everyday is very small and well-designed that stray capacitance is nearly absent. Thus, we can assume no stray capacitance in it. However, if it has stray capacitance, I guess it should be undesirable too because the capacitors in the electronic apparatus or machine have already hoped to have that capacitances for normal operation. If there exists any stray capacitance, the current in the apparatus may exceed the expected value which means the apparatus may not work well.