Using 'sit through' suggests patience or tolerance for something potentially long or tedious. The kids somehow sat through the five-hour opera.
Pro Tip 2/3
Not Enjoyable
The phrase often implies that the experience is not particularly enjoyable or is somewhat of a chore. She sat through the long play, checking her watch every few minutes.
Pro Tip 3/3
Unwilling Participant
Suggests participation due to obligation or lack of choice, rather than desire. He had to sit through his sister's piano recital.