When speaking with someone else, if they ever ask you to repeat yourself because they didn't hear or understand what you said the first time, always show patience and kindness while repeating yourself.
It's not uncommon to feel frustrated or impatient at having to repeat yourself. However, feeling frustration or impatience at having to repeat yourself doesn't mean that you need to show that to whoever you're speaking with.
There's all sorts of factors that can lead to someone not understanding you and needing you to repeat yourself. People can have auditory processing disorders, people can be hard of hearing, people can have a different first language than you, etc. Or even if someone doesn't have an auditory processing disorder, and isn't hard of hearing, and has the same first language as you, that doesn't mean they deserve to receive a snippy attitude just because they couldn't hear you or understand you the first time.
Either way, especially when someone just didn't understand you, it's always unkind and inconsiderate to be snippy or rude to someone just because they couldn't understand you. It makes life extra hard for marginalized groups, such as immigrants who have to regularly communicate in their second language, or people who are hard of hearing, when they have to deal with constant snippy attitudes or even cruelty from those who find it justifiable to be unkind to someone just for not being able to understand.
So the next time you're talking to someone, and they say something like "sorry I didn't hear/understand that, could you say that again?" or even just give you that blank lost expression universally recognized as "I didn't hear/understand what you just said", when you feel that frustration rising at having to repeat yourself, instead of getting snippy or showing any anger or aggression, take a breath and repeat yourself with patience.
Also please repeat the entire sentence, unless you are asked to repeat a specific part. Not only because you do not know which part of the sentence was missed, but also because if you repeat just the main noun, your audience will miss the context and implications of your sentence. It also helps your conversation partner to feel included, especially if you are in a group.
