How often do you hear about prayer at the meeting that, if you should pray that if Jehovah wills that He should do something? To me, this is a total waste of time to pray if that condition applies. You see, if Jehovah willed something, why would He need to wait for you to ask Him for it? Does Jehovah need your permission or request to do anything He damn well pleases? I don't think so.
Then, what about asking for something that He doesn't will? Is it possible, if Jehovah doesn't want something to happen or someone to get something, that a lousy request is going to change His will? Hardly. Once Jehovah wills against something, no amount of prayer is going to change that. Not even making deals and bargains: Jehovah will continually add more to your load while withholding fulfillment of the request in order to milk it for even more concessions. You don't get the thing you wanted. Jehovah gets extra from you. You have been scammed by the Almighty!
Basically, if Jehovah wants something to happen, He isn't going to wait for someone to ask before doing it: He is going to just go ahead and do it anyway. If He doesn't want something to happen, you are wasting your time trying to get through and get Him to change; He is only going to either dig in His heels and will it even farther away, or He is going to scam you into giving Him more and more service, milking it by withholding the things hoped for. Either way, praying is a total waste of time.
Besides, why thank Jehovah for doing what He wanted to do anyway?