i would say pachirisu, since you say you're cute and sweet and like being friends with people, but you're also warning people to not get on your bad side. it really reminds me of pachirisu because that's a really cute and sweet pokemon, but its mentioned that they hold grudges and have a short temper, which kinda says like what you said.its also an electric type, so... yeah. go stereotypical electric types! yay! but i feel like thats too obvious, so i think, although it doesn't seem like it fits very well, Chikorita.
Chikorita is a cute and sweet pokemon who likes being friends with people, and in the anime she falls in love with Ash or something. So when someone else likes Ash, she's shown to be really possessive and gets physical by attacking. So it's kinda like the other people who like Ash get on her bad side and she gets really angry. Of course, I don't know you, so I can't really say any more. But I still think Chikorita. or that might be because of my newly developed obsession for the johto grass starter.....