What are the refunds all about and why do all accountants always advertise it?

A new client who owes taxes and was a bit confused asked me this great question:

What are the refunds all about and why do all accountants always advertise it?

My answer:

Those refunds are a big incentive for people to file. 

Advertising "claim refunds you may be eligible for" is more effective than writing "file and pay your taxes or risk penalties, interest, levies and jail time". 

Plus most people aren't self employed so most don't end up owing taxes at tax filing time.

So that's why ads generally don't focus on the negative stuff.