Some (many?) may disagree, but dogs are like children. I find many parents of human children become offended at such a statement, which is often an invitation for comparison. I invite such an analysis (and ultimately realize we may never see eye-to-eye).
My dogs have and will always be a part of the family.
I play the role of parent, providing rules, guidelines and love. My dog plays the role of child, looking to me for structure, security and compassion. Ultimately, we are friends who feel incomplete when not together. It is an immeasurable bond.
More importantly, I take responsibility for my dog: providing nourishment, supplying shelter, socializing, protecting her from those seeking to cause her harm, preventing her from hurting others, and keeping her safe. Falling back on any one of these can have consequences for her, myself or even others. It is a lot to manage but I do it gladly. It may not mean, picking her up from school and packing her lunch (although it might with the popularity of doggie daycares) but I am responsible for the life of another living thing. I take that seriously, and yet, anyone can make mistakes.