There is a little trick that a lot of personal trainers use with their clients, and I am going to let you in on it.
Its called smoke and mirrors. Trickery. Deception. Chicanery. Bullshit, so to speak.
No, they don't do it maliciously. They do it in an effort to keep their clients interested. They do it because, otherwise, their session's lack substance. A lot of personal trainers find it extremely difficult to get results with their clients; for multiple reasons. If you only train someone once or twice a week you essentially only getting them for 2 hours per week; whatever they do with the other 166 hours each week is up to them. The biggest reason for most trainers is their lack of skill. It's possible to get clients to improve with only a few hours per week, but you have to approach it correctly. You can't get someone to become stronger, leaner and bigger all at the same time in just 2 hours per week.
One of the biggest tricks I see trainers pull with their clients is using excessively complex exercises. A complex exercise is one that combines several exercises into one. Example: reverse lunge with bicep curl to step-up with overhead press...on a Bosu ball...with a resistance band around your waist...and a live chipmunk in your pocket...while yodeling. Sounds fun, right? Use it with a client and watch them get dominated by the exercise. For an average person, the level of coordination needed will be a drain; added to the metabolic demand necessitated by an exercise that uses so many big muscle groups.
But what does it do? Nothing, really. An exercise with this many moving parts is going to be limited by the weakest exercise. In this instance, the client will probably be weakest in the bicep curl. Thus, they will be lunging, stepping and overhead pressing a super sub-maximal weight. So, you take 4 exercises and add them together to create one big exercise that is not challenging to anyone besides a beginner and is instantly limited in the amount of weight used, thus negating any potential benefits.
One of the sneaky reasons that a trainer will use these exercises is because it will make the client feel like they will be unable to do their workouts without the trainer. "Ooh, he knows so many fancy exercises I've never even heard of! I can't recreate a single thing we did together! He must be the tits!" This is how a shitty trainer gets/keeps clients. These guys have "new and exciting workouts all the time! Every session is different!" Unfortunately, these new and exciting workouts never amount to anything because they don't follow the basic principles of strength training. Sure, you burn a bunch of calories while you're doing it, but you could get the same metabolic effect by doing 15 minutes of intervals on the spin bike.
Another tactic is to use these overly complex and difficult exercises with someone who is brand new to working out, so that they get crushed. Then, the awful trainer will start in with the old "see what awful shape you're in? You NEED me!" These are clients that should be starting off with the basic/classic exercises: bodyweight squats, lunges pushups, etc and plenty of metabolic work.
It is much more difficult for a trainer to sell clients on a steady diet of squats, deadlifts, pressing and bodyweight exercises. Theres nothing sexy about that. People tend to think that those are things they can do on their own (p.s. they DON'T do them on their own). They also tend to think that they are "too easy" and that they have grown beyond them. Really? Grown beyond deadlifts? Some would say its impossible to outgrow an exercise: can you out-deadlift Andy Bolton? Have you plateaued? Then you haven't outgrown the lift. Just frigging do it.
I totally support going to see a fitness professional if you need some help getting in shape; but be wary of the people who are trying to lure you in with bells and whistles. If you don't mesh with someone, it's ok, try someone else. If they are a professional, they won't get butthurt about it. Stick to what works: the basics.
Go to the gym, do the basics....lift something heavy!