Everyday Spanish in Spain is direct and relaxed, but a few small words still open every door:

Spanish	English	When
Por favor	Please	With any request: Un café, por favor.
Gracias	Thank you	Muchas gracias — thank you very much
De nada	You're welcome	Literally “of nothing”
Perdón	Excuse me / Sorry	To get past someone, or for a small slip
Disculpa / Disculpe	Excuse me	To get someone's attention — disculpa to someone you call tú, disculpe to usted
Lo siento	I'm sorry	A real apology
Adiós	Goodbye
Hasta luego	See you later / Bye	Very common — even when you won't see them again soon