You're Welcome = Dou itashimashite
Go Ahead = Douzo
Nice to meet you = Yoroshiku Onegai Shimasu
First Time Meeting you = Hajime mashite
Before eating = Itadakimasu
After Eating = Gochisosama
Please = ___ kudasai (used when saying please do this / that etc)
= Onegai shimasu. (request)
= Dōzo. (offer)
= Onegai (used when asking a favour, so simply "please")
Setsunai = painful, trying, oppressive, suffocating