"Contractor or Madam?" joke

Top ten reasons why owning a plumbing contracting business is similar to running a bordello...
Most "service work" by employees is done either while kneeling, or while flat on their backs.
While on the job, most employees have their butt cracks, bare midriff, and other parts of their anatomy exposed.
When a customer hires you, they know up front they're going to pay through the nose.
Unless they've been through the process before, your customer tends to be very nervous initially, then accepting and even enjoying what's taking place during, and in the end, usually feel relaxed, and feel like that they've gotten their money's worth.
If they don't feel they've gotten their money's worth, the response is universally the same: "I've been screwed!"
The government, from local law enforcement to EPA to Public Health and everyone in between, is determined to drive you out of business with nit-picking regulations and stupid laws which criminalize innocent behavior.
Depending on the geographic location of your business, and the nature and predisposition of local officials, on rare occasions distasteful but necessary small bribes must be paid to grease the wheels of expediency, in order to stay in business.
After a long, hard day's work, most employees take a long, very hot, hard-scrubbing shower to remove the offal and residues off their bodies that's been put there from doing their difficult and smelly jobs all day long.
A lot of the "service work" done is paid for in cash, and some of it is even declared as taxable income.
No matter how well you do your job, the public-at-large still looks down their noses at you because of the stereotype of your occupation being a less-than-desirable one to make an honest living at, never giving you the respect you deserve as a committed, dedicated professional, even though most of them at some time during their lifetime will make use of the services you provide.