The way I was brought up, you always give a response when you were asked a question, because ignoring someone when being addressed is rude.
Even if you had no answer just then, you respond to acknowledge that you have heard the question, be it a nod, a smile, or some form of affirmation, and inform the person you will get back to him or her.
Of course there are questions that you think don't warrant a response, that you don't deign to respond, either because the question is outrageously ridiculous, blatantly provocative, or despicably offensive, in which case the person who questioned was just asking to be ignored; or because you are a snobbish prick, which is, well, rude.
I kept reminding my children to treat people how they want the others to treat them. I sure hope they incline towards the right and not the wrong behaviour!
If you always ignore the others, they will eventually ignore you. If you are always rude to the others, then eventually the nice people will distance themselves from you. If you always treat the others as backup, then eventually they will treat you as backup too.
Don't be self-centred, there may be some people who spoilt you so, but really, the world doesn't revolve around you.
Be nice, be polite, mind your language, mind your manner.