Restrooms are not appropriate places for cell phone conversations. The last time I checked, the bathroom stall did not replace the phone booth. Is there no modesty anywhere, any more?
I don’t want to hear your phone conversation while doing my business. I really don’t care about your social plans, your sex life, or your issues with your boss.
Don’t expect me to hold the flush or wait to blow dry my hands until you hang up. If the person on the other end discovers where you are, that’s your problem.
And finally, think about the germs that may be on your phone from the bathroom mist the next time you use it.