Why do adults think that our lives are so easy?

I mean, I get that their lives are undoubtedly harder than ours as teenagers, but that doesnt mean our lives are sunshine and rainbows all the time. We have to worry about stuff going on at home, school, friend drama, boyfriends and girlfriends, finals, semester changes, extra activities.... I have dance 4 days a week, both my dad and grandpa have cancer, I have finals coming up soon, my friends aren't speaking to me for reasons unknown, my boyfriend and I are getting to that rough patch where you "take a break...." Seriously, I've been so stressed lately and then our parents come and tell us our issues are miniscule compred to theirs? I dont mean to sound unnapreciative, but really, what can I do to let them know that, actually, no, my life is NOT lollipops and four leaf clovers?