I found it strange that Strava Activities are always a bit shorter than what my watch says.
And I know for a fact that my watch is correct, because when doing races, it is always spot on with the official times.

Let’s focus on my last activity. If I open it on strava and ask to create a route from my activity, this is what I get: 

At the bottom, it says 7.1Km, which is EXACTLY what my watch recorded for that route.

But if I look at the Activity map, it’s like I a taking shortcuts that are not possible, as it goes straight where the road curves:

 

The resut is 90m difference on a 7100m route:
 

This is sufficient to lower my pace by a few seconds, on this case, 5.04 to 5.07 and sometimes makes me miss, for example, the 10K badge, when running on a certified 10K route (it’s marked on the road...).

I have seen mention to a “correct distance” option on the website, if I click the three dots on the left menu, after opening the activity, but I have no such option, I am guessing it was removed?