Why wont youtube let me skip backwards and forwards like i want?

Lets say i watch a video on my phone and see something funny, and i want to see it again a few times. So drag the little thingy on the time bar thingy back to before the funny thing happens, so i can watch it again. But god-damned youtube says it cant let me do that and starts off where it was. So i drag the thingy back again, and still youtube says no. God damnit, who designed this shit. Is there any way i can stop this from happening? I just want to rewind a few seconds so i can watch the cat falling again, why wont this stupid app let me do that without pissing me off a few times first?