@4g: Say "we have to" with a "due to" - do not let us mix up a request with an urgent need! I once had an italian pilot on frequency requesting descent out of the cruising level, which was a complicated coordination due to airspace structure so I told him to stand by. After two times saying that he said that he canīt really do so because there is an engine on fire!
Avoiding wx is not a problem, just tell us you have to - in advance, please! Playing tricks is sometimes tolerated among a few of us. We do notice when the avoiding heading equals the direct routing to the destination. Insist on having to!