system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it when I can doze off in a matter of seconds watching tv, but if I immediately roll over and go to bed it takes much longer to go to sleep.
gpt
When you're watching TV, your brain is kind of on auto-pilot; you can't think, because you might miss something (even though you might miss something if you doze while viewing). 

When you quit watching TV, your brain starts to process all that TV information you just took in.