We can also call this person a sourpuss.

我们也可以称呼种为" 满腹牢骚的（sourpuss）" 。

Yeah, you weren't with the sourpuss all day.

你和个满腹牢骚的家伙呆一整天试试？

AII right. I guess that I'm the target of some backstage grumbIings.

好。我猜我是满腹牢骚的家伙的攻击目标。

Their gripe The emergence of new private cab services, known as voitures de tourisme avec chauffeur, which can be ordered via a mobile app.

他们对被称为voitures de tourisme avec chauffeur（司机驾驶）一新型私出租服务的出现满腹牢骚，一服务可以帮助们通过一个移动应用程序预定出租。

For once the European bit of NATO, determinedly led by France and Britain, took the initiative in a military campaign rather than meekly (or grumpily) following the Americans to war.

因为一旦北约中，英法为首的果决的欧洲力量，主动发起军事行动而不是温顺地（或者说满腹牢骚地）跟从美国作战。