Where Did I Go Wrong?

I'm so fed up of my big kids today, they are selfish and spiteful and I can't believe that I brought them up, I went wrong somewhere.
Without going into too much detail, big daughter was really mean to Lucy at breakfast time because she's not quite got the hang of holding a spoon properly and was making a mess with her cereal. It doesn't help that the younger one Leila can eat perfectly well, but it's out of order for her to start calling Lucy stupid and retarted. She made Lucy cry and I had to intervene ( I hadn't been in the room when it started but could hear what was going on) She did apologise to Lucy afterwards, but it was all totally uncalled for and something she does too frequently.
To make up for her meanness early big daughter came home from work with doughnuts. A bag for her and big son, and a bag for the girls. Big son come down and said "why did you buy 'them' doughnuts?" To which she replied "well they were 70p a bag or 2 for £1"
 So big son says, "well you could have saved both bags for us"
grrrrrrr, how mean! They barely ever think of the girls anyway, they don't get birthday cards or presents, or anything at christmas, now he's begrudging them a few doughnuts.
Then there is the money issue, always a problem.
I asked big daughter for her rent and she says she can't pay this week because she's just bought herself a tv for her room. So that means I have to use my weekend food money to pay her share of the rent. Big son pipes up, "you can lend it off me and I won't pay you next week!"
OH THANK YOU VERY MUCH.
So we'll go without food next week too because SHE can't pay her way!!!


How did they get like this? I really don't know, but I must be to blame.