Music Sampling good or bad?

What's your opinion about this? i was listening to this podcast and
they were discusing this topic. is this good or bad? i mean, Rihanna
sampled O-zone's Numa Numa Yei, enrique Iglesisas sampled Lionel
Richie's "all night long." im sure there are more songs sampled out
there. i was thinking it was bad because i like Lionel Richie's song,
and when i heard it on Enrique's song, i didn't know it was Lionel
Richie's...i thought it was 100% enrique's material.... enrique didn't
give credit to the original artist. so, what's your opinion on music
sampling?