Hard enough for two dogs to get along....

My Great-Grandfather had a saying "its hard enough for two dogs to get along, much less people".. does this apply to Christians too? I know that we as a group of messed up sinners coming together as the Body of Christ will obviously have a couple of disagreements...but it seems like lately there aren't alot of people on the same page...
I can't say that I feel like I am living a life of purpose and glory toward God right along side all the believers I know.
I know in my heart that we all believe, worship, love and adore the same God...why can't we put on a little bit more of a united front?
I read a quote the other day that hit me hard. Mother Teresa said "If you judge people you have no time to love them".
Is this the reason for little divisions between Christians? Have we gotten so used to the way things are divided (church by church/denomination by denomination) that we can't see the Body of Christ as a whole.....?