It's really important not to daydream when you're in the middle of doing something.
How many times have I been doing something and then drifted off, and later wondered if I'd done that thing I was in the middle of doing? Or how many times have I suddenly panicked, thinking I'd forgotten to do something, just because I was daydreaming while doing it? Like shampooing my hair twice or walking a great distance back to my car to check if it's locked.
One quite important tip I would like to offer (thankfully never happened to me) is never to daydream when you head to the public toilet. Everyone, at least once in their life, I'm sure, has opened the door on someone peeing or pooing. I did it just recently, on the plane back to Amsterdam.
I walked to the toilets and the door right in front of me was green, so I pushed it open... to find a big white man standing and peeing. Oh, thank goodness I didn't catch sight of his thingamajig with pee flowing out. Might have made it even harder for me to sleep on the plane (thankfully I managed to sleep relatively comfortably). All I could do was just quickly step back and let the door close. And I saw the door go red exactly when it closed. I think the guy sitting right next to the toilets saw what happened as well, because he was giving me a really dodgy and serious kinda face when I glanced at him. Geez, like it was my fault.
Another time I remember stumbling upon someone else was in a public toilet, and the cubicle door was green so obviously I pushed it open... to find a white girl squatting over the toilet.
This brings me to another point...
Of all my years of going to public toilets in Malaysia - and by this point, I mean to say that I've been to the same toilets with a majority of Asians - I've only ever stumbled on whites not locking their cubicle doors. Honestly, why is that?