Used mostly in casual conversation, not in professional or formal settings. I'd never say this at work, but his lateness is starting to get on my wick.
Pro Tip 2/3
British Slang
This phrase is British slang, so it might not be understood outside the UK. When I studied in the US, nobody understood when I said 'get on my wick.'
Pro Tip 3/3
Frustration Level
Suggests a growing level of irritation, not just a one-time annoyance. He's been humming the same tune all day, and it's really starting to get on my wick.