If a doctor cuts you open and take something out, you won't complain in fact you'll thank him and even pay him as you know he is doing it for your own good.
If he asks you to give something up you'll try, as again you trust his judgement and know he's telling you for your own good.
Similarly if Allah takes something from you, thank Him too as He is the doctor of all doctors. If He has taken something from you it is probably for your own good and if He has stopped you from something then again it is for your own good.
Is not Allah the most just of judges?