Am I the only one who feels...

Am I the only one who feels that the characters jump to their emotions too fast? I feel like all of them have bi-polar or something. One moment they are cool with one another, then someone says or does something basically irrelevant and all of a sudden they hate that person with all their heart.example being in season 2, Johnny and the rest are excited Mike is back. Mike says they are acting like burnouts and Johnny acts like Mike just smacked his mom.