Pretérito indefinido vs. Pretérito perfecto

Question

Is there are reason these sentences are in the pretérito perfecto:

La obra de teatro nos ha aburrido mucho

Me ha encantado tu actuación

The English translations aren't in the perfect. I could imagine saying "the play has bored us" and that carrying a somewhat different meaning than "the play bored us". Similarly, "I have loved your performance" might be something one would say to a regular company member who is leaving after 6 months in a role, while "I loved your performance" might be said to some immediately after seeing their show for the first time (in English). I am trying to understand the nuances of why you might use the perfect tense in Spanish when it seems like the indefinite tense would work as well (and in English would mean something different).

Answer

Hola R
without seeing any time phrase linked to the sentences it is a bit difficult to see the nuance. In Spanish, if you see an statement using the perfect tense like in these two sentences:

La obra de teatro nos ha aburrido mucho.
Me ha encantado tu actuación.

we assume that the speaker is referring to a very recent event, probably just minutes after the play finished. The perfect tense in Spanish generally talks about events that we feel are still linked to the moment of talking. 
If we had used the preterite instead:

La obra de teatro nos aburrió mucho.
Me encantó tu actuación.

the speaker would be referring to something that happened on a different day to today, e.g. ayer, el otro día, el año pasado; we would see these actions as completed actions, not linked to the present time at all. 
I think this lesson talking about the contrast between El Pretérito Perfecto and El Indefinido will help. Have a look here.
Saludos
Inma