Easy Come, Easy Go
I'll write more at length about this later, including some citations so you can see the science is real, but I want to put this out there so people understand it going in...
Your body works on a ricochet principle. The faster you lose weight, the faster you'll gain it back when you go off plan. The faster you gain muscle and strength, the faster you'll lose it if you go off plan.
If you want real, lasting changes, you've got to take your time. Take your time so you don't hurt yourself, and take your time to stabilize the gains you've accomplished. Because the opposite is also true. If you take your time to steadily and consistently build strength, even if you get hurt somehow, you won't lose all your strength while convalescing. And you won't gain back all your weight even though you can't move (so long as you don't binge junk food like a moron).
The reason I'm saying this at all is because people like to see change immediately from their efforts, and when they don't, they either get mad at themselves, mad at their trainers, or they just give up. If they quit, their trainer doesn't get paid, so the trainer is in a bind. The trainer has to keep giving the client quick results even if those results are not permanent because the techniques to get them are not sustainable.
Think of that show, The Biggest Loser; it showcased the absolute worst ways to train people, and yet that is so many people's expectation of what it takes to be in shape. That's nonsense. If you want to be healthy, you've got to take your time and keep consistently putting money in the bank through your lifestyle, every-single-day. There are no shortcuts here.
Consider your trainer and consider yourself. Don't put absurd, adolescent time frames on your own plans, whether that's gaining or losing. And don't put those absurd standards on your trainer. And don't let them put those standards on you! They know that to keep a client, they have to do the thing that client expects, so you tell them when you meet them: "I know a lot of people expect to lose/gain a silly amount of mass from just a month at the gym, but I know it takes months or years of consistent effort to achieve lasting body transformation." If they still want to train you in that TV ready way, then you'll know you need a different trainer, but if they're worth their salt, then letting them know you're willing to take your time will do you both a world of good.