The house always wins because we are losing more than we should have lost.
That's not the main reason why they always win, it's actually the house edge. Also, they don't win on a daily basis, but because they have the edge, gamblers will eventually lose in the long run. Do you think gamblers will patronize casinos if they lose every time they gamble? no, there are times they are lucky and they win, so they'll come back and lose, it's just an ordinary day but most gamblers do not really tally their cash in and out.
Consider gambling just as a means of entertainment and you will never have problems.
Good advice though.