Dark bits.

is a funny thing. 

You may decide to spend $5 on a hand job. To the casual observer, who also happens to be a pervert, it would seem that you believe a handjob is more valuable than the 5 dollars in your pocket. 

But, if someone were to offer you $1,000,000 or 200,000 hand jobs, you'd probably take the money.

Similarly, the guy who's giving you the hand job believes your 5 dollars is a better value than the service he provides.  But, if you gave him the opportunity to commit to giving 200,000 hand jobs for $1,000,000 dollars,  he'd probably say no.

None of this explains why I put 5 dollars in the vacation Jar every time I jack off, but it's interesting. 

p.s. trigger warning