It's packed, it's sweaty and the air is thick with tension. There's loud music playing and grunts coming from the corner. No, it's not the train in rush hour. It's the gym.
Every day after work, these rooms are packed with office workers sweating it out after a day stuck behind their desk.
The hairy sweaty men taking up the weight machines and the fitness fanatics, ferociously pumping the arms of the cross trainer like they are trying to take flight.
I can't be the only one who hates the gym, right?
I love exercising, but what is it about gyms that everyone goes crazy for? I just don't like the stuffiness, the lack of natural light, the crowds and the fact that it's expensive.
Not only are there more people going to the gym than ever before, but the birth of social media means they are telling you about it too.
There's nothing worse than those running apps that casually post on Facebook how many miles you've run on the treadmill that evening. Or even worse - gym selfies.
Not all of these people are telling the truth. 13 per cent of people who say they are going to the gym actually go somewhere else, according to a study commissioned by Kettler. The pub, perhaps?
Around a third of these people also admitted to never breaking a sweat in the gym.
13 per cent of people who say they are going to the gym actually go somewhere else
Maybe I'm being unfair. After all, it's a really easy way to squeeze in a workout into a busy day - particularly if your gym is right by your office.
They have top notch cross-trainers and weights machines that you could never afford in your own house.
Jogging in a city can be a treacherous pastime, particularly if you've got your headphones plugged in. You are not going to get run over in the gym (unless you're particularly cack-handed on the treadmill, like me).
I'm not saying kick it all in. If it's the only place you like exercising, then go for it. It's better to go to the gym than not exercise at all.
But what irritates me most is crap gyms that still charge crazy prices. The ones with rude reception staff, old machines, broken drinking fountains and changing rooms with damp verucca-breeding floors.
But they are quite happy to charge you over £40 a month for the pleasure of visiting.
Anyone else agree?