The One With Chandler In A Box - S4-E8
Monica: Fine, judge all you want to, but [to Ross] married a lesbian, [to Rachel] left a man at the altar, [to Phoebe] fell in love with a gay ice dancer, [to Joey] threw a girl's wooden leg in a fire, [to Chandler] LIVING IN A BOX!
The One With The 'Cuffs - S4-E3
Joanna: What are you doing?
Chandler: I'm getting dressed.
Joanna: Why?
Chandler: Because when I go outside naked, people throw garbage at me.
The One With The Girl From Poughkeepsie - S4-E10
Rachel: No accountants. Oh, and no one from, like, "legal." I don't like guys with boring jobs.
Chandler: Oh, and Ross was like what, a lion tamer?
Answer: The statements that she's contradicting (that it is common, it happens to every guy, and it's not a big deal), are the things that a woman commonly says to a man who is suffering from erectile difficulty, typically to assuage his bruised ego. However, most men do not believe that these statements are true, as evidenced by Chandler's outburst. He's so caught up in the proof that women are lying about it that he gives himself away.
Rooster of Doom