I work in fast food if you order fries no salt I purposely make them cold and soggy
That's rude, why do you do that?
I don't want customers to come back to me if they're going to ask for no salt.
Even if you are irritated by special food orders that make you work harder, you should serve your customers good quality food all the time. If you aren't working to the best of your ability and people complain, you could get in trouble at work. You should do your job well and serve good quality food to all customers.
I just work there for the money. No one really cares about me.
People usually request special orders because of a dietary issue. If they need no salt, there's could be a heart problem. Purposely giving them soggy and cold fries because of their health problem reflects poorly on you and the restaurant and you should stop.