¡Qué detalle!

Regalo, as you know, is gift. However, the associated verb regalar, gift (something), requires extra attention since it is used more widely in Spanish than its English counterpart.

¿Me regalas uno?

In English we might ask our waiter Could I have a napkin? Could you bring/give me a napkin? In Spanish, this kind of request is often handled with regalar, especially when requesting something you don't intend to return. ¿Me regalas una servilleta? Could I have a napkin?

Regalar is also used for asking small favors that involve giving something intangible. Here are some common cases:

• Asking for time: ¿Me regalas diez minutos? Could I have ten minutes of your time? (to talk or help me with something)
• Asking the time: ¿Me regalas la hora? What time is it?
• Signature: ¿Me regalas una firma? Please sign here.
• Beso: Regálame un beso, ¿no? Give me a kiss. Kiss me.

Su regalada gana

The common expression hace lo que se le dé/pegue la gana, he does whatever he feels like, has a more emphatic counterpart: Hace lo que se le dé/pegue su regalada gana. Use the appropriate possessive pronoun: mi, tu, su, etc.

Obsequio

By the way, if the gift in question is something small or symbolic, for example, something you might bring as a houseguest, it is common to refer to it is an obsequio rather than a regalo. We don't really have a special word for this in English, so it can be hard to remember to use. Te traje un obsequio. Gracias por el obsequio.

¡Qué detalle!

The word detalle is also used in the same sense: Mil gracias por el detalle de las flores. Thank you so much for the gesture (of bringing flowers). Un muy buen detalle de tu parte. The gift was very thoughtful.

When giving such a gift, you can say: Es un pequeño detalle. I brought you a little something, it's nothing. ¡Qué detalle! How thoughtful of you!