It's a mug's game, Mrs. Renton.

4 seconds sound clip from the Trainspotting (1996) movie soundboard.

You can hear this line at 00:54:07 in the Blu-ray version of the movie.

Quote context

[...]

- I appreciate what you're trying to do, I really do, but I just need one more score.

- Just bring me one more hit. I need one more fucking hit! You fuck! Hit. Hit.

- Well, this is a good fucking laugh, ain't it?

- You sweat that shite out of your system, 'cause if I come back and it's still here, I'll fucking kick it out. Okay.

- Question number one. The human immunodeficiency virus is a...

- Retrovirus?

- Retrovirus is the right answer!

- It's a mug's game, Mrs. Renton.

- I mean, I'm not saying I was blameless myself. But there comes a time when you have to turn your back on that nonsense and just say no.

- Just say no.

- She's gone! She's gone!

- Question number two. H.I.V. binds to which receptor on the host lymphocyte? Which receptor is that?

[...]