I didn’t choose to be a local guide - I still remember when I shared my first review was really because I had a great experience in a particular restaurant and I just had to write it down.
Then google prompted me to share more, and with all its integrated services (e.g. google photos) sharing on mobile was really easy, I didn’t even need to find the photos myself! So naturally I posted more and more without even knowing it.
I guess the best part about sharing is to let the world know there’s good food / a special place / a nice view, and it’s one and only for yourself but also can be many people’s favorite.
And it goes both ways - now before I go to any place I’d check google maps and find out what the local guides say about it first, it’s such a nice feeling reading about other’s experience and you just can’t wait to go and try it yourself. Sometimes you do have a different experience (good or bad) than other people but if you don’t try you never know.
Go my fellow local guides! Let’s make earth a better place 
or just find me my next dining place 