It was poor quality, sorry.
The deal is that it's hard to dunk a basketball. It's especially hard to dunk in games. It's extra-especially hard to dunk if you're only 6' 3", like Lin.
But beyond that, it was an amazing play by any standards (as Region says, that crossover dribble was a thing of beauty) but if it were Kobe Bryant, say, it would just be "there's Kobe being Kobe." Kobe was a high school phenom, top prospect, went straight from high school to the NBA. Kobe has always been Kobe, and has always been in the limelight.
Jeremy Lin, however, is some guy who's labored in the background for ages -- nobody who follows basketball, even pretty closely, had any idea who he was until 12 days ago. He went to Harvard and has been an anonymous back-up player -- he might come in for a short time in NBA games, towards the end, but had never started in an NBA game.
Then all of a sudden, when the Knicks lost at least two of their best players, the anonymous back-up player had to play more -- and didn't play like an anonymous back-up player!! Looked a lot more like a fancy starter. Which took everyone completely by surprise, and has been a lot of fun so far.
And also has meant a six-game winning streak for the formerly rather hapless Knicks. As in, it's not just a few tricky shots, he's really helping them win.