खुसी लाग्यो

Grammatically, yes (laagyo is the past form of laagnu). However, it is used to express an immediate present feeling that was triggered by something that just occurred.

Yes, you can say 'Uslai khusi laagyo' (He/She felt happy), but it's most commonly used in the first person to express your own feelings.

'Khusi' is common and everyday. 'Harsha' is formal, literary, and often used in religious or official contexts.

Add 'dherai' (धेरै) or 'ekdam' (एक्दम) before 'khusi'. Example: 'Dherai khusi laagyo!'

Yes, it's very common to say 'तपाईंको इमेल पाएर खुसी लाग्यो' (Happy to receive your email).

Absolutely. It is polite and respectful. Just ensure you use the honorific 'Tapa-lai' if you are addressing them directly.

Use the negative form: 'Khusi laagena' (खुसी लागेन).

In the context of emotions and sensations (hunger, cold, joy), yes. In other contexts, it can mean 'hit', 'attached', or 'started'.

It reflects a cultural view that emotions are experiences that come to you from the outside world or social interactions.

It's better to say 'Movie ramailo thiyo' (The movie was fun) or 'Movie man paryo' (I liked the movie). 'Khusi laagyo' is more for personal news or social encounters.