It all begins with expectations. We expect a WHOLE LOT from Rabbis. They are expected to be paragons of good character, scholars who can answer questions on the whole Torah, understanding counselors who can guide us through the maze of life, models of heightened spirituality etc. etc.
What is the reality? The reality is that Rabbis have character deficiencies. Some get angry, some are jealous at times, some are honor seekers and some can even be selfish.
A Rabbi who is an expert in the whole Torah is almost non-existent. To know Tanach and Shas and Shulchan Aruch and the Zohar and writings of the Arizal etc. etc. is virtually impossible. Abaye already said in the gemara אורייתא מי איכא דידע לה is anybody really a master at the whole Torah?
Some Rabbis are emotionally attuned and great life counselors while many are more scholarly and their strong point is the intellect and not emotion.
Some Rabbis are very spiritual people whose davening is inspiring. Others find davening boring and their zest is for more mechanical parts of serving Hashem. [I recently heard a Rabbi publicly admit this. The problem is he seemed to be a peace with this....]
MY POINT is that Rabbis are fallible human beings. Does this mean that we shouldn't have special respect for them? Of course not! We should accord them the greatest amount of respect because we appreciate what they have and all of their wonderful qualities and the Torah that they DO know.
When I was a kid I thought that Rabbis were super human. Later I found out the truth. A fine example: I once sent an old Rebbe of mine an email saying hello and asking how he is. He answered some time later and respectfully [he called me "Rav"] told me to bug off :-). Did I lose respect for him? No! He still has many wonderful qualities and is a great teacher but I do think [from knowing him for a long time] that maybe his interpersonal skills could use some polishing. So in Torah in his area of specialty I would defer to him but when it comes to "people issues" he would not be my model.
Some complain: "I can't talk to my Rebbe in Yeshiva about my problems because he doesn't/understand/have time/ seem to care." My answer is that not every educator is an expert at psychology [either, by the way, is every psychologist]. So if he says a geshmake gemara shiur and can make a tosphos dance, enjoy and respect him for the great Torah he teaches and find another Rebbe for personal issues. If one isn't satisfied by his wife in certain areas he must accept this and come to terms with it as there is no substitute. We have only one wife [if we are fortunate]. But if ones Rebbe doesn't "supply the goods" in all areas it is a.o.k. to go to a different Rav for what you need.
If someone is having a shalom bayis problem I wouldn't necessarily send him to Rav Chaim Knievsky Shlita. I don't expect him to be a marriage counselor. Maybe that's not "his thing". Maybe it is. I really don't know. But if someone wants to know a source anywhere in the whole Torah he is the address. I revere him because he is a gadol baTorah but don't expect him to be a jack of all trades. Maybe he is, but as a human being it is more likely that he doesn't excel in EVERY area of life.
Some Tzadikim are experts in Kabbala. So they would be the address for more mystical questions such as naming children. A Young Israel Rabbi may be a great leader and speaker but he wouldn't necessarily know the secrets of the hidden wisdom. Usually he doesn't. Do we respect him less. Of course not. We respect him for his great drashos on Shabbos and for his leadership skills.
There is so much good to find in people there is no reason to harp on their faults. A mature person with a balanced view of life is able to appreciate that people are people and we can't expect anybody to be great at EVERYTHING. Often, a simple layman will possess various qualities that his Rabbi might lack. He should still ask the Rabbi halachic questions while realizing that the Rabbi isn't perfect, but who is??
In summary [when I was taught in elementary school to write essays they said I should conclude with "in summary" or "in conclusion"]: Respect Rabbis. Respect gedolim even more. Don't be turned off if you discover their inadequacies. Appreciate them for what they offer and in every area search for the right individual. Poskim for halachic questions, educators for educational questions, emotionally attuned Rabbonim for advice on personal issues.
And don't forget תמיד בשמחה.
Love and blessings!