I am one of two children, the oldest. Then when my parents got divorced they both remarried to people who both had three boys of their own. I was now the oldest of seven brothers. Technically, I had one step brother who was a little bit older, but his maturity level was so small that I got all the burdens of being the oldest child. 

The oldest child is frequently given the most responsibility. Trust me, it sucks being responsible for your brothers sneaking friends into the house while your parents are out of town when you cannot get them to leave. I am only the older sister, I didn't have any authority over them so my brothers just ignored me while my parents expected me to keep them under control. I got blamed for a lot of things that I couldn't have controlled and had a lot of responsibility that shouldn't have been mine. As an eight-year-old I was responsible for waking my six-year-old brother up and making his lunch. This was hard on me and strained my relationship with my parents.

Another downfall of being the oldest is that my parents were SO strict with me. They had never had a child go through high school before, never had a child with a heart break, etc; this made for a lot more rules. I know I wasn't allowed to have a boyfriend until I was fifteen (I ignored this rule, of course) and my brother was allowed to have a girlfriend at age twelve. I was forced to spend a lot of the weekends with my family until high school whereas my younger brother had a lot more freedom when he reached middle school. 

I admit, I had psychological factors that played into some of these rules but for the most part, being the oldest is generally pretty stressful. Your parents want to be part of your life, you're their first, their baby.