I've been guilty of:
- buying domain names with no purpose other than owning them (what I called domain hoading for those of you who have seen A&E's tv show)
- Believing that getting $1 PPC revenue over 1 year was somehow justification that the domain name renewal was worth it. Umm, math anyone?
- Buying multiple related domain names with no purpose
- Forgetting to undo automatic renewal on Godaddy
Okay, now I feel better! Rip on me if you want, I deserve it!