why toppers lie?

i hv seen that toppers themselves they take coaching but after selection they say that i didnt do any coching.. what is the reason that toppers tell lies? why they cannot be honest.. similarly i hv seen tht some ppl who are clearing prilims and main join mentorship program,test series bt wen u ask them dey say i hd very bad experience... why such hypocrisy?? why such misleading?