What are the similarities between Protestants and Catholics?

Protestants are churches or groups of people who have broken away from the Roman Catholic church and/or each other in protest over some belief(s) or other. Depending on what they have denied will determine what their similarities are. As far as worship is concerned, the closer they are to the Church the more similar their worship service will be. Anglicans, for instance, are very close, maintaining the buildings that once belonged to the Church, and having a Communion service which is remarkably similar to the Mass, howbeit with the sacrificial elements removed. Quakers, Pentecostals, and Baptists on the other hand are far removed from a Catholic service. Similarly in beliefs, Martin Luther denied some very basic elements of the faith, but remained fairly close to the Christian church, Wesley denied even what Martin Luther retained, and others have denied both. Once you leave the Holy Roman Church, you have left the protection of the Holy Spirit, which Jesus had guaranteed to His church, and without that protection, splinter groups and new denominations breed very fast. I have heard that currently (2010 A.D.) there are over 30,000 different Protestant religions.