Daisy- Nick seems to think she's just as frivolous and "useless" so to speak as the rest of the upper class that just parties all the time.
Gatsby- He fascinates Nick, but he is also very suspicious of him after all the rumors and whatnot.
Tom- Nick views him as just a brute because of the way he treats women and pretends to know a lot.
Jordan- Obviously he thinks she's very deceitful, but that attracts him to her because opposites attract and he is very lonely.
The meeting in Ch. 5- It seemed to make Nick happy to see his cousin who was very hollow to be actually happy. He also felt sort of awkward since he was alone.
Meeting Tom's mistress- Nick didn't seem to want to at the beginning and would much rather not no, but since Tom insisted when he met her he seemed to think even less of Tom. Tom was clearly just in it for the "physical relationship" so to speak. He also didn't seem to think much of Myrtle besides that she wasn't the brightest and was trying really hard to fit in with the upper class despite being an outsider.
Nick's first party at Gatsby's house- He gets a real taste of what Gatsby's riches truly are. He seems to be even more intrigued by Gatsby and the rumors that surround him since everyone seems to have a different story. This also sealed Nick's attraction to him.