I have yet to meet an SEI who does not admit to being a pack rat. I live with an SEI. Here are a couple examples of his pack-ratedness.
My mom bought some small lunchables. We ate them. SEI liked the way the plastic bottoms were shaped. So he collected them and stashed them in the piano bench. Later, my SLE brother (youngest) saw them and tried to throw them away. SEI yelled and cried and didn't let SLE clear them out.
Our church wanted some paper towel rolls for some craft projects. My mom got a few slightly smashed ones collected. SEI noticed, went into his room, and brought out a handful of quality paper towel rolls. My mom and I stared. He suggested more and went back into his room. He completely filled a grocery bag with paper towel tubes that he had stashed away.