why?

An old friend of mine I haven't talked to for years now committed suicide. I found out yesterday. She was a neighbor across the street from where I grew up. I used to annoyingly show up at her door as a frustrated kid who was looking for somewhere to be other than home. It was usually at the inconvenient hour of dinner time. She'd have just gotten home and would be making dinner for her and her boyfriend, she'd invite me in and I'd watch her cook, and talk to her about random things. Then she'd ask if I wanted to stay and watch TV with them. She was very kind and inviting to a clearly troubled and depressed kid. I can't help wondering what had gotten her so down on life, and sadly wishing it would have come full circle for her, that she would have had a listening ear and encourager around when she really needed one. Even though we lost touch when I moved away from home, and I haven't spoken to her in years, I can't shake the heaviness I feel.