Names

Peeping tom
One who derives pleasure, usually sexual, from secretly spying on others
(See voyeurism.)
‡ The original “peeping Tom” was a legendary resident of the town where Lady Godiva rode naked through the streets. According to the story, Tom defied official orders by looking out his window as she went by and was struck blind.

Doubting Thomas
One who is habitually doubtful. For example, He was a doubting Thomas about the coming merger, not believing it would ever happen. The term alludes to the disciple Thomas, who doubted Jesus's resurrection until he had first-hand evidence of it (John 20:24–29).
Keeping up with the joneses

Striving to achieve or own as much as the people around you: “If you want to keep up with the Joneses in this neighborhood, you will have to own at least three cars.”

I Don't Know Him From Adam:
I wouldn't be able to distinguish that person from the most important person in human history. Or perhaps, he is as remote and unknown to me as is Adam.
I Don't Know Him From Adam's Off Ox:
really don't know him
Smart Alec
A smart Alec is a conceited person who likes to show off how clever and knowledgeable they are.
Jack of all trades.
A person who can do many different kinds of work.

Tom Dick or Harry
Robbing peter to pay paul
Take from one to give to another, shift resources. For example, They took out a second mortgage on their house so they could buy a condo in Florida—they're robbing Peter to pay Paul. Although legend has it that this expression alludes to appropriating the estates of St. Peter's Church, in Westminster, London, to pay for the repairs of St. Paul's Cathedral in the 1800s, the saying first appeared in a work by John Wycliffe about 1382.
before you could say jack robinson
Very suddenly or quickly; in a trice.