In the story "Dusk" by Saki why is the young man not in a very good mood?

The young man is not really in a bad mood but is only
putting on an act in order to attract Norman Gortsby's attention and start a
conversation. This act would seem to be a bit of reverse psychology. Ordinarily a man
who is looking for a handout will be polite and pleasant. He will approach the other
person with a friendly smile. This young confidence trickster has figured out that there
are too many panhandlers behaving the same way. If he behaves in just the opposite way,
by not smiling, by not being polite and pleasant, he can perhaps achieve two results:
(1) he will attract more attention and interest; (2) he will not be taken for a
panhandler.

The young man intends to explain his bad mood
with his complicated story about losing his hotel when he went out to buy a cake of
soap. He does succeed in getting Gortsby to listen to the entire story, but he does not
succeed in convincing him that his story is true. The con man can hardly expect the
story to work every time. He is playing a numbers game. If he can only succeed with one
person each evening he can earn several hundred pounds a year without really working.
(The average clerk's salary in those days was one pound a
week.)

When Gortsby, who turns out to be unexpectedly
sophisticated, exposes the young man as a fraud because he doesn't have the cake of
soap, he puts the trickster in a really bad mood. The con man has only an hour or two in
which to operate before it gets too dark and cold for likely prospects to be staying
outdoors. He goes off in a huff because he has wasted too much of his valuable time
going through his whole routine with a deadhead.

Gortsby
was right about him from the start. Then Gortsby found a cake of soap and became wrong
about the con man. Then when Gortsby learns that the soap belonged to someone else, he
realizes he was right about the con man in the first place, but now he is out one
sovereign as a painful lesson. He should have trusted his instincts. There was another
flaw in the con man's scam. Why didn't he just go to another hotel and tell his story to
the desk clerk and ask to be trusted overnight? Isn't that more sensible than going
around telling his cock-and-bull story to perfect strangers in a public park? Gortsby
should have wondered about that. The con man wouldn't go to a hotel, of course, because
he didn't want to stay in a hotel.