The mirror enables very quick checking of any activity behind me at crucial moments when I need to know this but at the same time spend as little time as possible taking my eyes off where I’m going. It’s incredibly useful in heavy, fast traffic on complicated roads like my London commute.
I find it very useful and a safeguard against accidents. Like this morning.
I fail to see why that makes me a “tit”, ernie. Perhaps you could explain why that is, unless of course you are simply using the thread to hurl some abuse my way, in which case I think you need to be moderated.