I call myself lucky regarding my friendships and connections. Not lucky because no matter what I do they're always there for me, no. Lucky because I had the opportunity to make a connection with them. After that, my friendship relations require a lot of effort, but that's why I give them so much value.
Through time, I've been blessed and cursed with some connections I made. Cursed in a good and a bad way. In a bad way because I took things by granted, and mistook acquainted people by friends, and trusted too much on who I shouldn't have trusted, or even made too much pressure on some connections trying to force them to be good friendships (by mistake, not forcing it in a creepy stalker way haha)... When I mean 'cursed in a good way' is dooming a connections in order to get another one, with the same person. Like some sort of upgrade. But I considered it cursed because, just like an upgrade of something, you loose some functions from the old version. Functions you were used to and knew you could rely on. You get virgin ground, without knowing where is it safe to step. If you are able to dance all over the floor, or if you will fall into an abyss as soon as you step forward. If is there any safe path you can take, or if you must be dodging holes the hole walk. If you can keep doing what you used to do before, or if the new connections obliges you to move on and adapt, to forget what 'used to be' and embrace the new way of looking to that person.
All in all, connections are always good. Even if they won't last, you can always learn something from them. And maybe the best connections are the ones that don't last, but you keep them in your mind for the rest of your days.