I think the worst experience I've ever had was when I ate hash-cakes. I ate four of them in quick succession, not really realising how much it would affect me. Shit hit me all at once... and every time I breathed my eyes would kind of have this flaring sensation.. like they turned into nostrils and were expanding and contracting along with my lungs. I got really fidgety. Spent six hours continuously lying down, getting up, heaving but not actually producing vomit, lying down again, etc... Fucking awful. The worst I've ever had from booze is just needing to sleep an entire day to get over the hangover. I've definitely had worse times on weed than I have on booze.