Intensity is built in the mind - not in the environment you workout in. You don't need to be cussin' and shouting and slapping yourself in the face to have a great workout.
There's a million different gyms out there with a huge variety of different atmospheres, machines and colours. The trick is - To make sure you're going in with the right head space.
You see, To ensure that you can workout to a capacity that allows you to progress - You must mentally prepare yourself for what you're going to do. If your workout is going a long distance 10 mile run - You better get ready for continual pace for a solid hour+.
If you're doing Crossfit? You better get ready for quick short sharp burst with intensity and lung fatigue throughout.
Choose your music accordingly for both of the above.
Ultimately though, the people who really last and the people that really get somewhere with exercise are those who don't put too much worry in to it. Don't put your workout on a pedestal. Get your headphones in and go to work.
Do that day in - day out and you'll begin to compound your progress.
It's much easier to get it done than it is to sit and worry about how you're going to do it. And remember - Your intensity is YOUR intensity - Nobody elses.