My comments are open to everyone, so please use them, otherwise the invite will be ignored when I see it.

What are good reasons:
We have a common interest in games and maybe you want to play with me sometime.
We are already acquainted well enough elsewhere. (Keep in mind I'm not mind reader. Telling me who you are in advance sure does help, unless it's obvious)


What are bad reasons:
You saw that I'm a mod in the /r/Steam discord and want help. Well you can ask for help there, not here.
You saw an old trade listing published from me. Well, I'm not trading right now. Taking an extended break. This can change, but for now, no....
Having no reason...