You need a cable with an angled plug of the right length and thickness. Not that common. The Tesla cables cost $14 (!). The profit margin must be Apple-like, which is probably why they are no longer included for free.
Financially - this is a non issue.
Annoyance wise - it would have been high up on my WTF list. Charging your cell phone while driving is standard practice for just about everyone, and having a convenient way to do so was the only thing I asked the delivery guy to help show me when I got my TM3P.
Saving $14 (more like $1.40 in actual cost for Tesla) seams like a dumb thing to do if Tesla cared about customer experience. BTW, none of the nearby delivery center stock anything, so in addition to figure out what's missing, a new customer will now need to order the stupid cable online
w.r.t. NEMA 5-15 (120V receptacle, aka L1) vs. 14-50 (240V one, aka L2): the former are widely available, but usually wired into 15Amp circuits, which will provided token minimal charging of ~3 miles per hour charging. Practically useless, unless you are stuck in a middle of a desert on empty battery, and have 4 days to spare to charge it.
The latter are wired into 40-50Amp circuits in all modern homes, and could actually charge your Tesla battery overnight.
Again, a very dubious "upgrade" by Tesla.
*sigh*
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