Photo credit: wallpaperscraft.com
Another word from the gym, but not necessarily sport-related… Towards the end of the sound system in the class started playing up and we ended up doing the last five minutes in silence. To which the instructor said ‘It’s a good job it didn’t happen 45 minutes ago’ (it would have been no fun!)
This is a very popular colloquial expression, which means ‘we are lucky because something happened or didn’t happen’.
You could also say, for instance, ‘It’s a good job I took an umbrella’ or ‘It’s a good job I remembered to bring my ID – the shop assistant thought I was under 25 and didn’t want to sell me beer’ (something that still happens to my 30-year-old husband quite often).
Confessions of the Linguistic Spy 