It's hard to find a group of competent players who play at/better than your current skill level. It's also hard finding people who play in your normal time frame. Likesay you have a static doing Coil, one doesn't show up due to <insert reason here> and no coil that day. Sure, you could have a backup player, but who likes being backup? Everything else is easily puggable. Tome grinding? Pug. AK? Pug. Coil? Can try a pug, but chances are you might get shit on.