Addicts don't typically have rational thought. AMber clearly needed help that NO ONE was willing to give her. The rehab she went to on the show was a joke.
Amber could have gone and gotten the incredible amounts of help that have been available to her for years.
She chooses not to. I get she's an addict and it's not that simple, but she is also choosing to not do anything about being an addict - or a h.s. dropout, or etc., etc.
I don't actually get the notion that she cares particularly for Leah - her interactions with her from the beginning have seemed entirely fake to me, like what she thinks maternal love is supposed to look or sound like.
I also suspect she went to jail because it was simpler than dealing with getting in trouble, having to pretend to not use, etc., all the time. In jail she can just hang out and get high and whine about how bad her life is because of Gary and how much she misses Leah and whatever else she feels will garner sympathy.
C&T are on the show, imo, because they're the only redeeming things about it. They're the most mature people on the show, all other Teen Mom's parents included, they seem to have a stable, respectful, adult relationship; they speak to each other with respect and deal with things as adults. They take care of their completely immature, useless parents (sometimes save Tyler's mother) - to the point of sending April supportive flowers in last week's episode.
They have jobs (Maci - that's when you leave the house for something besides whining to your girlfriends about your endless bf drama), they're trying. They're not doing everything right, or on time, no.
However, if you said two kids were born to high school dropout addict parents who lived in a desperately economically depressed area, who were repeatedly arrested and jailed for all manner of things and those teens themselves got pregnant in h.s. - the odds of two years later both of them having graduated h.s., having jobs (and they don't even "have" to, given the MTV money, but they both do), having made the choice they did with the baby, being on their own in a stable relationship, in a clean, safe living space of their own? Astronomical.