I just have to list how many times the references to TIME in the first ten minutes of Back to the Future. How many are there?
Starting from 00:00 to 10.00
1) Ticking sound heard over BttF logo
1.5) Approx 15 clocks in the Doc's room (of various types include mechanical, pendulum and electronic), a Heath-Robinsonesque can opener, a timer toaster oven and a timer coffee maker
2) Satirical picture of Harold Lloyd holding onto a clock hand
3) News broadcast informs us that it's 1985.
4) Call from the doc asking Marty to be at the mall for 1:15
4.5) Doc advises us that the chiming clocks are wrong and that it's 8.25 (Late for school)
5) Marty passes some parking meters.
6) Clock outside Mayor Goldie Wilson's campaign offices
7) Strickland is looking for Marty to give him a "tardy" slip.
8) Marty blames the doc for his clocks being late.
9) Strickland gives Marty his well-earned warning for being late.
10) Marty asserts that "history is gonna change".
11) Clock outside Goodwill store.
12) Marty is worried that record execs will tell him he's "...got no future"
13) 'Save the Clock Tower' demonstration in background
14) Ruined clock tower in the background.
15) More parking meters.