If I watch 2 or 3 of someone's vids in a row - an intro will push me away. Especially a long one. Long being anything over 4 seconds. I flash a logo, and that is all. I used to have an intro but realized I hated sitting through other people's opening credits. So I moved mine to the end of my vid, and still cut the length by 50%.
There are some channels I watch that have a long intro (20-30 seconds). I always click ahead on the scrub bar. If I click too far, no worries. I would rather miss a few seconds of the vid, that sit through opening credits.
Maybe that is just me...