Since most elderly people are orphans, that makes retirement homes orphanages, amirite?

Except orphan refers specifically to children so unless their parents kicked it when they were kids, it isnt.

We could eventually end up selling usernames like we do domains. amirite?

I have hoped for this, actually. I have a very very common last name, and can't ever get an email address or username that doesn't have to include many random numbers. I would happily pay for a simple username.

You can milk any mammal and drink their milk, amirite?

Okay..milk me then

Roundabouts are like crop-circles for roads, amirite?
If they take you out to a restaurant like Applebee's, you're the side piece. amirite?

You got it backwards.

Earrings can be dildos if you're brave enough

Given the time we all spend on electronic devices we could start using electricity as global currency, amirite?

Energy is already a global currency.

Avalanches are real life physics glitches, amirite?

Why? It's just snow going down a hill

Hub caps are only found on really cheap cars and really expensive cars, nothing in between. amirite?
Most celebrities wouldn't be considered attractive if they were normal people. amirite?
The sincerest form of betrayal is ordering French fries and receiving sweet potato fries. amirite
A Red apple actually exists as Cyan. amirite?
Stars make light.... and human beings... amirite?

If you mean humans create light then yes but they don't emit light.

Parasites are less cared about than one would think, they are so creepy. amirite

By definition human fetuses are parasites.... and they are creepy

Pulling on it won't make it any bigger, amirite?