The phrase "annoying lag" refers to a delay or slow response in the functioning of a device or system that is irritating or bothersome. Full definition
I've also noticed a moderately annoying lag between the time you press a key with your finger and the time when a letter pops up on the screen. (liliputing.com)
Active digitiser needs to super smooth and with zero lag or least annoying lag for faster note taking abilities. (goodereader.com)
But in the Signature Touch we find ourselves afflicted with annoying lag that comes and goes, at times seizing up the entire phone for seconds. (androidcentral.com)