Just curious. (apologize also for not-so-standard English)
I really don’t use it as much as I should, I should give people more credit. But I pretty much use it for the same reasons as you. I guess as I do it so infrequently it should be considered an honor if I’ve liked somebodies post…hehe.
On one of my other forums we even have a dislike feature, which is actually rarely used but I’ve found invaluable to keeping the trolls away, trolls who care what other people think anyway I suppose. I’m not suggesting such a feature here in any way but it is an interesting way of keeping the peace.
I agree with you. Use it wisely. 
Sometimes there is confusion over whether to ‘like’ a post that has something sad or depressing in it. I believe that ‘liking’ a post suggests that one likes the post itself and the fact that something was shared, not that they like what happened.
I have the same confusion, too. It might cause that member thought that I “overgloat over someone else’s misfortune".
Exactly.
When someone writes “my pet died, I’m very sad… But I’m working to get over this loss and I will get better” I do give them a “like” 
as a show of support. Not as a show that I’m glad their pet has passed away.
I also use the “Like this Post” function for something that makes me laugh out loud or that inspires me.
Those 3, and also if something is deeply profound, humorous, or is a sync with something I was just thinking…
I guess it will all go with support the member…but I really don’t do the just give away or give and take thing… if someone likes my post i want it to be because they like what I said for some reason and if I like someones post its because I liked it…
Finally, I have more likes given than likes received.