I am abnormally lazy in that respect. I've been known to get up, walk across the room, turn off the alarm clock, walk back to bed, sit down, think "hmm, 5 more minutes would be great" and then go back to sleep, responsibilities be damned.
My first job out of college was a start-up in the financial industry; strolling in at 11am was highly looked down upon, and so ended my budding career as a finance whore.
I find that, for the first few seconds or minutes after waking up, I'm not even capable of rationalising that I'd rather get up and deal with the consequences of being tired. This is far longer than the time it actually takes me to fall back asleep.
I cured myself of that by getting a radio alarm and turning it up as loud as it would go; I basically shocked myself totally awake first thing. Nowadays just an ordinary alarm is enough because I have made it a habit to get up. (If you are not going to get up when the alarm goes off, don't set it - you will just be training yourself in the bad habit of ignoring it.)
Added: One of my responsibilities was to make sure my brothers got up in time for school. I can tell you from experience, that if you have someone to help, ice water is a great motivator to get out of bed.
My first job out of college was a start-up in the financial industry; strolling in at 11am was highly looked down upon, and so ended my budding career as a finance whore.