I grew up with a stepdad for a while. He favored my brother (his biological son), and I don't really blame him for that. He was around for some time though. He traveled a lot, and as a result we never really had to worry about anything financially. Nonetheless, my mom decided to divorce my stepdad when I turned nine.
All in all, I do think I missed out on a lot. I never had a legitimate connection with my then stepdad, so that resulted in negative aspects. For example, I'm fascinated by baseball and always have been. I played for a while, and he never helped me get any better so I stopped playing and lost my love for a while. While I was losing my love of it, he went and helped my brother become pretty damn good. Anything that a dad stereotypically does with his son, we didn't do. I had a "father-son" time once, at my urging, on one of his business trips. I just got in the way, but I was happy. When we came back, I learned he called my mom to get my little brother some expensive toy because he didn't take him.
In the past few years I started driving, and I would kill to understand cars. My brother understands them and is going to take over his dad's mechanic business after he goes to university. I don't envy much, but I envy people who had a dad that taught them how to drive or taught them about cars. I have questions about life and I don't have a father figure to talk to them about.
After their divorce, I lost a lot of what I had. I lost stability of being able to say "dad". I still resent that word because it represents something that I never had, and never will have. I lost a connection to a male who would be able to help me through things I wasn't comfortable involving my mom or sister with (notably puberty). I lost a part of what I consider a building block of life, and it makes me choke up to this day.
I'm almost 19, though, and I have a hell of a lot left to learn. And frankly, I'll be damned if not having a father is going to stop me.