Is it only me who feels guilty for the nasty face I must pull? I don't mean to, but sometimes it's the surprise of their choice. I'm really not a snob, people should call their babies whatever they like and other people should shut up. But sometimes I have a visceral reaction, just can't believe someone in real life has chosen that name.
What do you say, how best to distract from such unexpected dislike?
Do you mean you must pull a nasty face (in which case why?) or you think that your face must betray your inward feelings? I don't have an issue with Gus particularly, although I'd ask what his full name was and feel a bit "why" if it was just Gus (hate shortenings as given names me). The only name I really struggled to respond positively to in person was an "America" I met at a baby gym class once. Think I just didn't say anything.
If you can't hide the look on your face you had better not ask people in RL IMO it would be incredibly hurtful for the parents to see this better phone or text them and ask the name if you aren't able to control yourself