Why are some people's life so inconsistent?

I know mine sure is. Things start looking up for a few weeks and then I'll end up back in the same rut I was in. Some might say this is life, but not really. I mean I don't know everyone's life but I know not everyone is constantly up and down. Sometimes I figure it's just cause life isn't fair maybe and some people are just gonna struggle more no matter what they do. Idk. Maybe that's just my pessimistic side speaking. What do you guys think?

I think that's just how things are.  Every major and most minor religions on Earth have at their core an attempt to alleviate the admitted suffering that just is living on planet Earth.  Until I started mindfulness meditation, and actually applying mindfulness to my life and trying to live life only in the here and now did I really start to overcome some of the inherent inconsistencies and suffering.  A wise man once said, "you can plan a pretty picnic, but you can't predict the weather."  - Outkast.  Also the personal struggle is a personal one.  It's subjective and most of us are good at hiding it from others.  So we really have no idea what another may be going through at any given time.  Someone you think has it together may be worse off than you.  They may think you've got it made.  I really just think that's how things are and have always been, and the best way to deal with it is to live for this moment, and not worry about the rest of it.  That takes time and practice, though.