I'd be careful, old timer. This is a rough neighborhood.

2 seconds sound clip from the Back to the Future Part II movie soundboard.

You can hear this line at 00:30:51.984 in the Blu-ray version of the movie.

Quote context

[...]

- We can't risk you running into your older self.

- Come on, Einie, let's go. Where's Jennifer? Where's Jennifer?

- Hilldale. This is bitching.

- One, seven, four point five zero.

- That will be $174.50.

- Here.

- I'd be careful, old timer. This is a rough neighborhood.

- Where's my receipt?

- Right here. Here it is.

- Hello. How about a tip?

- That accident caused a chain reaction that sent Marty's life straight down the tubes.

- If not for that accident, your father's life would have turned out very differently. The man in the Rolls-Royce wouldn't have pressed charges, Marty wouldn't have broken his hand...

[...]