is there such thing as appearing TOO confident during a job interview

[skim milk]

Usually I tend to be nervous with phone interviews but today, with the right alignment of events, I felt confident when picking up that phone. It was a really important interview for me but it ended a lot quicker than expected. He barely asked any questions.... the interview ended in 25 minutes.. (too short isn't it?)
I tend to talk fast so I'm not sure how he perceived that. He might've gotten the impression that I was trying to rush it but that wasn't the case.

Anyway, at the end, I wanted to get his contact information so I asked him to email me. Was this too cocky to a Manager at the firm?
I wasn't trying to be cocky, one of my other interviewers in the past said he'll email me with this contact info and it worked out fine but what do you think? I thought it was a stupid mistake so I quickly found his contact information through google and shot him a thank you email.

 

[Chronoshock]

I wouldn't worry about it, the thank you email will get your intent across. Unless you think you're an arrogant douche, you probably didn't come across that way, you probably just sounded nervous. Phone interviews are generally quick since its not really enjoyable for either party, so typically between 30 minutes to an hour.