<human>: I remember this one time when my family was out fishing at the pier, my parents lent my younger sister one of my jackets. I think this was when I was about 10. Of course, I'm very possessive over the things I own, because of many instances similar to that one time where I brought home a small bag of candy as a gift from my teacher only to find it in my sister's stocking Christmas morning (and having only ate a few pieces)... The anger and tears I shed only to get myself punished for putting up a tantrum... And no candy. :(

Anyways, I told my parents I didn't want her to have it. The jacket wasn't really an issue. The issue was that they didn't ask me before just giving my things away. (They did this often. They gave away my newly acquired (but used) Dreamcast and games because I already had an N64. I didn't even get to use it more than twice.) They brushed me off. Fine. I silently fume for a while. Literally 5 minutes later, a seagull flies by, and lands a shit right on the jacket she's wearing. 

And I laughed in her face and refused to take that jacket back. 

My sister didn't really do anything, but to a child's mind, even an unwitting accomplice was still an accomplice.

Can you condense the text into three sentences or less?
<bot>: I have issues with people taking my things without asking. When I was about 10, parents gave sister my jacket. Bird took a shit on it while she was wearing it. I laughed in her face.