I have been taught that they are used when receiving something (or a favor) from someone. But how exactly do they differ? I've searched the web for an answer and.. One site suggests that kuremasu is impolite, moraimasu is normal and itadakimasu is polite. Another site says that kuremasu is just normal, and itadakimasu is very polite... I was wondering which one to use in which situations... or should I just stick to itadakimasu to be safe? are there any scenarios where it would be inappropriate?

I have been taught that they are used when receiving something (or a favor) from someone. But how exactly do they differ? I've searched the web for an answer and

• One site suggests that くれます is impolite, もらいます is normal and いただきます is polite.
• Another site says that くれます is just normal, and いただきます is very polite.

I was wondering which one to use in which situations. Or should I just stick to いただきます to be safe? Are there any scenarios where it would be inappropriate?