There are people that I have missed for decades.
I miss friends that have been dead for twenty years, thirty even and think of them often.
ofcourse...if they touched your life in someway, they'll always be in your heart.
Of course it is. I miss my friend after 10 years, my mum, my dad and my brother... sometimes it is like they never really left me though.
No, you should only miss a dead friend for about a week or two.
personally yes, I think it is completely normal