Mimblewimble, because it's just annoying more than anything.

Accio and Reparo...

Priortum Locomoter

Rictussempra or Tarantellegra bc they’re both equally useful and funny

I don't think it would be a specific spell, but it would probably be that I'd use Transfiguration spells more often. Melofors, Pullus, that sort of thing.

The Knockback Jinx

Levicorpus and Reducto

Muffliato

The Aveda Kadev...

I mean cruci...

Imper...

JUST ALL OF THEM

Scourgify. Because I hate washing clothes and utensils and even myself.