Which form of a shortstacker is the most annoying?

[donkeykong2]

I thought about making another vote thread, but as no one will answer if they could already vote i dont make another awesome vote thread.
so what size of a buyin is most annoying for a shortstacker to have against you?
10 big blinds, 20bb 30bb 40bb 50bb?
I often find myself clueless how to handle shortstacks as i dont know how they play. What strategy do decent (or bad) shortstacks generally use and how can you adjust to that?