What sparks the feeling of failure?

Today I ran into an old friend I'd lost touch with. Someone I always enjoyed spending time with. Funny, caring, helpful, a devoted husband, and wonderful friend. He mentioned he was ill (again) and it hit me like a bus. I immediately felt like I'd failed at being a friend. I'd fell out of touch, not bothered to put myself out there, stayed home when I should have visited and just in general felt a huge empty heart.

I know in my head that these feelings aren't valid, that I am a decent caring person and life just gets in the way sometimes. But I can't help but feel like I often don't put myself out there enough. I tend stick to working in the studio, doing barn chores, errands and the like but often not reaching out to connect with friends. Locally for sure, it seems I often see my US friends more than my Canadian ones.

It's interesting what can spark feelings of failure and how it can affect our thoughts. Has anything sparked a feeling of failure with you?