Yoda: You are reckless!
Obi-wan: So was I, if you remember.

Because, even in TPM he was a mature, clear headed dude. Maybe when he was younger, but then again Yoda never taught him anyway (unless maybe when he was like 4 years old) because it goes, Yoda - Dooku - Qui-Gon - Obi-Wan. But then I'm just making excuses for the crappy PT anyway.