this is all about manner. Remember this, no matter how educated or rich you are, your manner is what people are going to value you. Either they are going to respect you or not.
I believe when someone texted you, it is apart of your manner to reply at least with "ok" , "thank you" or "sorry" ... No matter how busy you are, at least respond to them, no matter how long it takes you to respond. It doesn't take a minute to reply with "i'm busy will reply later" if you are that busy. It is what we call as manner, especially when it is something important, especially when they ask for your favor or asking a question. I even reply the text even next day, telling i'm sorry that I was busy yesterday and I always take less than one second to reply someone's text when it is something important ( related with academic purpose or your mak cik text you ke).
Unless lah member kau just say hi or just wanna chat with you ,, ok la fine. you boleh reply later,, let say dia wassap kau pagi kau reply la before tido. Biadap kot kalau tak reply langsung unless kau memang nak friendzone dia. Bila orang dah buat baik dengan kau, berbudi bahasa lah.
Susah ke nak berbudi bahasa dalam alam maya ni? Paling tak lepas baca text dalam kuliah tak sempat nak reply nanti kena cekup dengan lecturer yang tengah mengajar, make sure lepas kelas tu cepat-cepat reply text. Let them know you are busy (tapi jangan jadikan tu alasan untuk menipu).
ok, I get pissed off even when my lecturer just left me with bluetick after my long text. At least, reply with "ok". Tapi sebab tu pensyarah nak buat macam mana. Tapi kalau kau ni just kawan,, memang lah you irked me to the core. Actually malu jugak bila nampak macam kita je beria and terhegeh nak start a conversation. Serious rasa macam jatuh lah pride bila kena layan macam tu..
I always tried my best to reply even aku tengah marah dengan orang tu sebab aku fikir, manner. Adab. Orang tengok kita ni bukan hanya pada luaran, tapi pada adab. Lagi satu, aku rasa biar orang buat kita, jangan kita buat orang.
p/s : Tak per, I always believe, what you give you will get back. Hidup ni sentiasa adil dan umpama roda. Life is like a spinning wheel, you don't always be at the top so watch your manner, Mr. may fate fare you better.