Focus on Your Phone
Little is ruder than staring at your phone while someone is talking to you. If you are on a date with someone, they should be your focus. They have taken the time out of their schedule to share an afternoon or evening with you. Respect their time and their energy. They agreed to spend time with you, not empty air while you grunt monosyllabic answers and stare at Instagram. You can do that at home alone instead of wasting your date’s time.
If you have agreed to go on a date with someone, you are assuming that they are interesting enough to be worth getting to know better. So, you should be able to keep yourself entertained by talking with them and not need to stare into your phone. Ignoring or interrupting anyone in favor of staring at your phone is rude, but it is especially poor form on a date. Telling your date to “hang on” while you check your notifications is a clear way to tell them “you are not interesting or important enough to hold my attention.” If you favor your phone over your date, expect your next date to involve you and the screen alone.