Why do we not make a Bracha (e.g. every morning) on the mitzvah of honoring one's parents?
The Rashb"a writes in his Tshuvos Volume I: siman 18 that kibud av vaim is like tzdakkah and charity is dependent on the receiver because maybe he will refuse to accept, and he (the giver) won't be able to perform the mitzvah. When the action of the mitzvah is not completely dependent on the giver then there is no bracha (from Sefer Pisgamei Oraisa which talks about many mitzvos without brachas and the reasons why).
I think with most mitzvos between man and fellow man (bein adam lachaveiro) there's no bracha; I believe it has to do with "how do we know you're doing it for the sake of the mitzva?"
But with regards to the question of why no bracha over saying the Passover Hagadah, they point out that to say "okay G-d you commanded me to show gratitude so now I'm doing it" doesn't sound right. So imagine it:
"Chaim, can you please bring the groceries?"
"Um, wait a minute Mom. Thank you Hashem, you COMMANDED me to honor my parents ... Okay Mom yes I'll bring in the groceries."
The thought process should be a bit more natural!
Also, it's further complicated (as it is with many acts to fellow man) by the fact that a given action may or may not be kibud av v'em. You can feed your father the finest aged steak and degrade him ("just eat the food and be quiet, old man!"); or you could have him hard at work at the millstone and still be honoring him ("if not for the millwork they would have drafted you, I'm so sorry dad.")
It is an ongoing mitzva that one is required to do at all times; therefore, you don't make a bracha. (Source - אור זרוע, ברכת המוציא, ק״מ. See also שדי חמד אסיפת דינים מערכת ברכות אות ט״ז)
We do not make a Bracha on Kibud Av Vaim as by each person the Kibud manifests itself differently.