I always prefer to have a fitness machine to myself. Million Dollar Exercise Review Who wants to share. However, there are times in which you must share. After all, you don't own the gym nor did you rent out this fitness machine. In any case, as you do need to rest between sets, it's perfectly alright to share the equipment with at least one other person.
This also goes for any other cardio machine. If you come to the gym when it's crowded, expect to be able to complete only 20 – 30 minutes of cardio. What can you do. There are other people too. Some gyms limit this as part of their guidelines.
I'm not asking you not to sweat. By all means, if you're not sweating it likely means that you didn't do a strong enough workout. However, no one needs to bask in your sweat puddles after you've completed your workout. First of all, place a towel on any machine you work with. Second, wipe after yourself. It's common courtesy.
You wouldn't leave weights strewn on the floor in your home, would you. By the same token, you should return the weights you use to their stand when you're done. Not only do weights pose a risk of tripping when they're left on the floor, someone needs to pick them up after you. Totally uncool. Basically, don't do anything at the gym which you wouldn't want to be done to you. Simple as that.