I think that for those of us who are mudansha have a sense of pressure to want to succeed and not let down our instructor and/or ourselves. Now that I am an Ikkyu, I do not feel the pressure and when I am to be tested for Shodan, I know I will be ready.
Funny.. In my experience the pressure builds even more after entering the yudansha grades. Previously somebody were ready to give me opinions on my level and readiness... now when I'm a yudansha and I run a dojo it is up to me to decide when I am ready to grade.. and letting your students down feels a lot more scary than letting your teacher down - at least in my book..
Well.. aikido is not objective but it was quite interesting that I feel so different from you.