I agree. The more angry you get while doing Aikido (as opposed to, say karate) is abd for your technique. Last night we were working on a technique, and I couldn't get it right, no matter what I tried. I continually got frustrated. Then when Shihan was my uke, he showed me what I was doing wrong and not to worry, and, now that I was no longer angry, performed the technique correctly (on shihan no less... although he was probably falling for me).
I notice that when people in karate get angry, the uke gets hurt. In Aikido, when people get angry, the nage gets hurt.
Such is the truth, such is the philosophy of O-sensei.