Too reliant/attached for what?Also, is it the strength of the attachment that matters, or the (in)security of it? All the attachment crayzness that comes to my mind is based on strong insecure attachment. Are there any examples of secure attachment getting out of hand?

Too attached for your T to have the skill and sensitivity to handle it - that seems happen a lot. Or, from the other side, too attached to feel safe / fully function in the relationship - yes, very possible. So dependent on your T that you stop (or never start) taking your own initiative - also happens. . And could probably go on for a while. But these are (nearly?) always a co-production between the therapist and the client.

Personal example: I got crazy attached to xT. I tried very hard not to, but due to her lack of cooperation and other circumstances, I fell into the exact sort of very painful and chaotic transference that I was trying to avoid by going very slowly and carefully. My attempts to somehow make the thing safer after the fact also failed. In terms of what I needed to get better, I think I was about as attached as needed to get, except it was to the wrong person, which made it too attached in the end. I'm far less attached to new T (she cooperates where xT didn't), which feels safer and I'm more functional,. BUT it somehow doesn't feel enough. Will see where things go from here.

I’m just wondering if people can become too attached or reliant on therapists for general well-being.
I think basically yes. Although it might be a necessary step for some people, but in that case it should be temporary and actively worked on. Like, those people you mention, who excessively try to contact their therapist? The therapist should address that and come up with a strategy to help the client cope better (although that might not always be possible), because if it's distressing to the therapist, it's a hunderd times more distressing to the client, to be in that state of dependency.

Hmm, I also recall reading articles about negative 'side effects' of therapy, which mentions this is a possibility, even without therapist mess-up (and therapists mess up more often than they like to admit) (could try to find the link again)

My worry in general has always been that I’ll have a relationship with a therapist and either experience transference or a sense of loss when expecting a therapist to be available at all times.

Haha that sounds faMILiar.

And there’s some scenarios where I’ve seen people nearly demand near constant contact to the point that they have a profound sense of loss when they can’t get a response. I’ve even heard of people who were told ( and agreed to) not have outside contact unless it’s an emergency. And even what constitutes an emergency. Does anyone see this as an unhealthy pattern or expectation? Does anyone agree that a therapist deserves time off when not in session?

I think it's 'unhealthy' in the sense that it likely comes from a place of serious psychological damage. However, since therapy is supposed to help with said damage, it'd be quite unreasonable to expect 'healthy' behaviour from these clients. Moreover, my therapists keep telling me that part of how therapy works is that the client's usual 'unhealthy' patterns/ways of interaction/etc are bound to emerge in the therapeutic relationship and so can be understood and worked on. If handled well, this stuff can be 'healthy' in the sense that it might be a step on the way to healing. It's the therapists' responsibility to keep their boundaries firm enough to not get overwhelmed and get the time off they need and deserve, but flexible enough to accommodate clients with extra needs. Some therapists provide transitional objects, or have other strategies to help with that.

I think what you write about your friend's therapist sounds pretty reasonable as far as maintaining boundaries goes.