Is it normal to wake up smiling after dreaming

Okay, so i've had dreams of killing people before but only the more gruesome killings are the ones that concern me because i always wake up with a smile and am very relaxed. My most recent dream was worse then the others. i started off scared and trying to hide, i found a Swiss army knife but instead of using the knife itself i used what looked like a nail file with a hooked end.
It was all relatively normal up till i started attacking him in self defense. However when he caught the file in his hand is when i started to lose myself. I remember grabbing his wrist and pulling down as hard as i could creating a huge gash in his palm and blood covering my hands. i began slashing at his arms slowly then i became more precise and made them deeper. It felt like my eyes would have been dilated and i was laughing, my head was filled with thoughts of watching him bleed to death and it became pure ecstasy as i watched the fear grow in his eyes.
He tried to run and i watched as he tripped over everything, i was laughing hysterically. i cupped my face with my blood covered hands and started saying how much i wanted to slit his throat and watch the life drain from his eyes has his body spasmed beneath me. I lunged towards him and that's when i woke up; i had a huge smile on my face, a warm feeling in my stomach and i was completely relaxed...
Is this normal or should i be concerned?