I have a 'weekend' switch where focus and willpower disappear and I start drinking and eating pizzas like the world's ending.
If you spend a lot of weekend time riding long distances at excessive speeds and eating accordingly, then maybe you've developed a Pavlovian response to weekends.
There could be some truth in that. But I think there's also the thought of reward for a week of work and the reduced threat of tiredness/hangover due to a lie-in on a Saturday.
When my training ramps up, I start to lose the lie-ins and I'll probably cut back a bit on Fridays.
I have a 'weekend' switch where focus and willpower disappear and I start drinking and eating pizzas like the world's ending.