Allah a sadist?

Volume 7, Book 70, Number 548:
Narrated Abu Huraira:
Allah's Apostle said, "If Allah wants to do good to somebody, He afflicts him with trials."

1) Which divine being would consider doing good to somebody by affliciting them with trials?
2) Wouldn't the devil be the one who wants to cause human beings misery and hardship?
3) Wouldn't a passionate and loving God not go out of its way to PERSONALLY afflict them with trials?
4) What good comes out of personally overseeing harm to others?
5) Will Allah be doing a good thing to those who are in the hell fire when he performs one of his many sadistic acts to the "unbelievers"?

004.056 YUSUFALI: Those who reject our Signs, We shall soon cast into the Fire: as often as their skins are roasted through, We shall change them for fresh skins, that they may taste the penalty: for Allah is Exalted in Power, Wise.

6) If Allah is doing a good thing to a person by afflicting them with trials, wouldnt it be better to be an unbeliever so that Allah may afflict you his sadistic acts (trials) which are in fact good for you?

7) Once again, does Bukhari try to glint who Allah truly is?