You can use 1 thu'um in real life, which are you picking?

I feel like bend will or slow time would probably have the most use irl, but you can't go wrong but animal allegiance, become ethereal, or clear skies either.

Of course call dragon/summon durnehviir would fuck up anything you want fucked up really easy

Dragon summon doesn't create a dragon though, it just calls one you already know.

As you said, slow time probably has the most real world application for a normal person that doesn't immediately out you as having super powers.

You could probably make a lot of money off of clear skies, you could sell your services to halt hurricanes and other dangerous weather wherever they appear, but you'd have a lot of crazy people trying to kill you and governments and big companies everywhere would want to capture and study you to replicate your ability.

Clear skies would also be nice for any sort of outdoor event you wanna go to a sporting event but there's a rain out/delay? Fixed. Wanna go camping but it's storming out? Fixed.

Bend Will was my immediate answer.

Everything else is either too situational, or doesn't really apply in a non-fantasy world.