Every Tuesday we cook tacos for dinner
I love tacos, Tuesday is the day after Monday but before Wednesday, that's the perfect day for tacos!
Exactly!  It's close enough to the beginning of the week to make it a special treat day
Internationally, Tuesday is regarded as the second day of the week!
Are the days of the week the same all over the world?
Yes, in their own language, but the start of the week changes, for instance in the US - Tuesday is considered the third day of the week.
Oh that's cool!  I always consider it day 2.  Are there other characteristics Tuesday would have that another day does not?
Not that I'm aware of, most cultures derive it's name from various gods/deities though.  Latin for instance, named the day after Mars, the Ancient Greek Ares.