Mind the gap: how good are we at keeping our distance?

During the Covid-19 pandemic, many countries instigated regulations to encourage us all to physically keep 2 meters apart when we encountered people outside our households or support bubbles, a practice commonly referred to as social distancing by (inter) governmental organizations such as the WHO, the NHS, and the CDC. Anecdotally, however, this distancing appears to have been hard to put into practice: Maybe you've experienced someone reach over you to get a box of pasta from a supermarket shelf (or even done it yourself).