I use Chrome. After I watch any video at YouTube it connects to another one without even asking. How can I delete that, so that one video finishes, that's all?
YouTube started an autoplay experiment last year.
Here's YouTube's guide on how to turn off autoplay.
You can turn off autoplay in your browser so that it is disabled for all videos, as long as they are not in a playlist. Here’s how to turn off autoplay:
Click the gear icon in the corner of the video player
Select OFF next to the Autoplay option
Alternatively, you can use the toggle above the Up Next section on the video page to turn off autoplay.
Note that autoplay will remain turned off until you turn it back on again.