Present Continuous – Correctness of “While You Are Washing Your Hands, I’ll Go to My Bedroom and Change My Clothes”

As mentioned, watch you doing is not the present continuous form but doing is a gerund and in the same way,watch you do is not the present simple form but do is a bare infinitive. Both choices are correct depending on what you want to say.

1. "I want to watch you wash the car" means that I want to see the action (washing the car) completed.

2."I want to watch you washing the car" means that I want to see a part of the action not the whole of it.

When native speakers say

I'm always {doing something}....

it's as if they're gently berating themselves that they persist in making the same error or slip-up.

I'm always misplacing my car keys!

I'm always forgetting my wallet!

I'm always mistaking him for his older brother!

Those are things you find yourself doing again and again. Such statements are an exclamation, more or less.

You can express a similar idea with simple present.

I always misplace my car keys!

but for many speakers the simple present wouldn't be as gentle and forgiving as the continuous, and there would be a little tinge of angry frustration in the statement.

What would NOT be idiomatic is to use the present continuous to refer to your standard (volitional/intentional) practice:

I am always eating lunch at that restaurant because it's close to my office. ^{not idiomatic}