One of the things about pride is that it blinds us. Very few people who are behaving proudly recognize it; they always find a justification for their actions. Selfish pride was the cause of the fall of the devil and he wants everyone to join him in it. When we consider our vocation before the Lord we all must be clear on what we are called to do. Pride is something that we can all fall into (whether clergy or laity makes no difference), and that will always prevent us from serving God rightly. Let us then look closely at what pride does to us when we are serving God.
Proud people always bluster around and boast about their knowledge, experience and superiority to others; humble people just do their job quietly and let others figure out whether they have knowledge, experience or reasons to be honored. Proud people always refuse to honor those over them, Jesus honored His Father so we could learn from His example and honor Him. He taught us how to fulfill our calling.
One of the reasons why the Catholic Church forbids men from putting themselves forward for ordination is because we should never trust our own assessment of our abilities. Certainly a man needs to have the desire to be ordained to the priesthood, but that is not the only grounds for determining his call; there also must be the call from the Church (as seen through his family, the local parish, and the clergy who are over him).
I remember once as a protestant seeing a man abandon his faith entirely because he did not pass his ordination exam for the Presbyterian Church. He had decided what he was supposed to be, and when others did not agree, he dumped the whole thing.
What about the rest of the duties in the Church that are not clergy oriented? When people decide that they have to serve in a particular capacity (or multiple ones), they can get it in their head that this is the only way that they can serve God (which is terribly un-catholic). They think things like "Jesus has gifted me so I have to do this" or "I have always done this, so I can't stop".
Whatever capacity it is that a layman serves in the Church, nothing can be considered a "calling" or "vocation" in the same way that ordination is. A layman may like what has done, but that does not mean that the Church is required to allow him to serve in that way. This is the reason why most of the lay services are ordinarily temporary (altar servers, readers, catechists, etc.). Every one of them is said to be appointed "temporarily" and one of the most noticeable reasons is to avoid giving anyone the sense of being "ordained" to the duty ("this is my arena, don't touch it!" is not a healthy perspective in lay service). This is the reason for the distinction between the ministerial priesthood and the priesthood of the laity -- each has their place and duty and they do not overlap (this is standard Catholic teaching; see, the Catechism of the Catholic Church, 1547).
Religious vows are permanent. Clergy vows are permanent. Lay service in the Church is temporary. Another reason for this because laity are allowed to assist Bishops, Priests, and Deacons, but their true area of service is not the Church but the world. They are called to be the shining lights of Christ in the secular realm. That is their permanent calling; this is what the clergy are supposed to equip them for: to do a better job in spreading the gospel in their neighborhoods, in the workplace, in the many places they interact with the world.
I know that this might sound contrary to what you have been taught. One of the biggest errors of the abuse of Vatican II teachings is to downplay the activity of the clergy and insert laity into many of those duties (as though the previous 2000 years of clerical activity somehow failed). It is also a big push by modernists who want to protestantize the Catholic Church. To allow laity to assist when needed is fine, it is not the normal work of the Church. In fact, many laity have been taught that every layperson needs to have a duty in the Church or they are unfaithful. If this were true, then very little of the ministry of laity in the world would happen. This is not what God intended. Let us each recognize the call of God on our lives and do our utmost to fulfill it with the grace of Christ.