a question and some venting

Does anyone know why God blesses some but not others?

My sister always seems blessed to get what ever she wants with little to no effort while I seem to be cursed with never getting anything i want no matter how hard i try.
Some examples
A few years back there was a new gym opening up close by and they were having a job fair so i went and did well on the interveiw and they said they would call back for a second interveiw and that is just one of many jobs i didnt get. Now my sister applied for her first job doesnt even fill out the application correctly and still gets it.
I was working hard in college to achieve my childhood dream of working in film and while in school i was having all these doors opening for me only to have them all of the sudden slam close in my face. Now my sis was able to get her dream job while still in school and was working two jobs as i couldnt get one.
So shortly after i graduated my grandma had a stroke and couldnt be left alone so since i was unemeployed i got the job of taking care of her and pretty much said good bye to my dreams but my sister agreed to take care of my grandma one day a week so i could have a day off that was until a she decided to move out almost two years ago .and hasnt given me a day off since. So now she gets all this freedom to go to bible studies, to date do hang out with friends and doesnt do anything to help out her family and i get stuck taking care of my sick grandma and now my sick mom and i cant even get time to go see a movie.

Sorry for the negitve post i've been having a bad couple of weeks and just needed to vent but if anyone does have an answer to my question please let me know

Ok i'm crying
As soon as I posted the first post my dad called me and told me he would pay for me to run in the Avengers 5k and not to worry about one of the things that really upset me yesterday.
It really meant a lot and the timing couldnt have been more perfect

There is a very real threat of sounding glib or expounding mindless platitudes when dealing with this kind of issue; so understand that I am not trying to do that. I have had severe anxiety and panic attacks for most of my life, so this topic has definitely come up for me... I'll try to relate what I have come to believe on the matter.

"Does anyone know why God blesses some but not others?"
No.
Not really. It would be nice to have that answer, but it isn't straightforward. Think of Jesus talking about the Tower of Siloam...were they particularly sinful people? Nope, something bad happened to them, that's all. Or the passage from Matthew 5 where Jesus says that God makes the sun and rain to happen to both the just and unjust.

Often there are just items in play that are outside our scope to change... is your sister good looking? Because if she is, I'll tell you right now that any job where people are seen, whoever does the hiring would rather have a good looking woman that can possibly learn the job than a good looking competent guy. One brings in customers, the other doesn't (but can help keep customers). Or maybe it isn't looks, maybe you just rubbed the interviewer the wrong way...or he was feeling a little ill or his wife was mad at him that morning... who knows?

There is another thing to consider. It is also possible that God has blessed you by NOT giving you what you want at the time you want it. Maybe you get the gym job and two years later in an attempt to keep up with the meat-heads you are pumping steroids or that one clumsy patron drops a dumbell on your head... Maybe you would have met a Delilah or Jezebel and gone down a dark path because of it. Or maybe it is simpler and because you haven't been blessed how you wanted you question God and draw closer to Him? Maybe you'd just be a luke-warm Christian without the trials you face...only fit to be spat out.
Maybe people just take advantage of you because you are in a position to be taken advantage of. "Well, hey, Rickster doesn't have a job, he should take care of granny..." Which makes good sense, but doesn't take consideration of you.
Maybe YOU aren't the issue here... Maybe your grandmother really needed some ministration that only you could give her. Maybe your sister would have gotten sick of her and been mean, maybe your sister would have felt the same issues you feel, but turned away from God because of them. Maybe some dude down the road that you've never met needed to see someone taking care of their grandmother so his heart would be softened toward his own.

Maybe poop just happens, and happens to you. I don't have the answer, but hopefully there is something here that can help in some way.

I want to echo Mikel and say I have no magic words and really want to avoid answers that are too neat and tidy to be of any use.

I've tried to avoid pain and discomfort my whole life, but the older I get the more I realize that suffering comes to pretty much everyone. Even if it's not until late in life when the mind and body degenerate and dignity and companionship are lost in the final years. I hope to train myself to "suffer well" when the time comes for me. For now, I'm trying to burn into my mind a couple of truths.

1. Romans 8:18-39(too long to quote here)

2. John 16:33 I have said these things to you, that in me you may have peace. In the world you will have tribulation. But take heart; I have overcome the world.”

Jesus knows firsthand what it is to be taken advantage of and overlooked by both strangers and close family and friends. And he's somehow using even the evil he permits to create the best of all possible outcomes.

I couldn't begin to guess God's specific reasons for what you're going through, but if I can be of any specific help please let me know. Hang in there.