Recently Taiwanese people say 自我感覺良好 (Zi4 Wo3 Gan3 Jue2 Liang2 Hao3) a lot. Is there some saying in English that represents the same thing?
The closest thing I can think of is Will Smith in Prince of Bel-air saying in a condescending tone “huh, you are really feeling good about yourself, aren’t you.”
self-delusional
smug?
conceited
I think self-delusional and self-conceited comes pretty close. But they sound a little more severe in tone. Also 自我感覺良好 has a oblivious feel to it, where as self-delusional and self-conceited might implicate purposefully doing so.
self-absorbed 
oh yeah… totally forgot about that one @_@ thanks
Hi, I am Taiwanese, then here share my view with you.
“自我感覺良好” is some kind of new phrase in resent years in Taiwan.
And it’s specifically been used in a euphemistic or humorous way of expression.
Though this sentence is pretty simple and in the meaning of arrogant or self-proud.
自我＝self
感覺＝feel, see, think
良好＝good, great, awesome
In other words, someone feels that he is so good, far beyond what he actually is.
By the way, usually we say “驕傲”, “傲慢”, “自大”, “自負”, “自滿” , “自命不凡” or “自視甚高” to describe someone arrogant in a certain aspect.
Hope that’s helpful.
(Breathing life into an old thread) I love to come up with translations for trending slang terms. The above-listed ones are pretty good. I would personally go with “patting oneself on the back.”
i.e. 近日政府新聞稿是一面倒的「自我感覺良好」
The government’s press releases of late have been one-sided exercises in patting themselves on the back.
The Carpenters’ “on top of the world”? 
[quote=“ntsigma”]Hi, I am Taiwanese, then here share my view with you.
“自我感覺良好” is some kind of new phrase in resent years in Taiwan.
And it’s specifically been used in a euphemistic or humorous way of expression.
Though this sentence is pretty simple and in the meaning of arrogant or self-proud.
自我＝self
感覺＝feel, see, think
良好＝good, great, awesome
In other words, someone feels that he is so good, far beyond what he actually is.
By the way, usually we say “驕傲”, “傲慢”, “自大”, “自負”, “自滿” , “自命不凡” or “自視甚高” to describe someone arrogant in a certain aspect.
Hope that’s helpful.[/quote]
This is a really good and useful explanation and I’m surprised nobody has thanked you for it. 
I think it’s hard to come up with a term that translates 自我感覺良好 exactly.
I’d go with the phrase “to have an overly high opinion of oneself.”