Single-hand clock showing percentage of today that's already gone
Time is flying. Make the most out of what's remaining today. Carpe diem!
The clock-hand shows how much percentage of time has elapsed since the start of the day.
Just by noon you'll see that 50% of the day is gone.
While opening a new tab, the clock's presence would make you to subconsciously evaluate your priorities (for the day) and so there's less chance you'll open a distracting website!