They usually have maintenance on Monday so that day is pretty unplayable because of whatever they're doing, god knows what because things only get worse and nothings ever fixed(LOL).
Tuesday you may be able to play, but there's an influx of people who wanted to play Monday and couldn't because of scheduled maintenance.
Friday-Sunday as expected is a laggy mess, as is the current state of the game at this very moment, multiple crashes and dashboards.
Basically, if you wanna have the best experience(which is pretty bad) wedsday-thursday are the best days for you.
But hey, what incentive does ZoS actually have to fix anything or up performance when people are throwing money at them for cosmetic changes.
I'm a PVE roleplayer concerned about my vampires stage 4 skin tone and keep getting load screens so I came here to distract people from major issues with a rant thread about my characters cosmetic appearance.