Preface: I've been playing guitar for 9ish months now... I started on an acoustic and I've played quite a bit with my roommate's electric.

I've always seen the electric guitar as being far less forgiving than the acoustic when it comes to technical mistakes. Missing the fret by a little bit, strumming the bass strings a tad louder than you were expecting: big problems with an electric, but not really problems I've faced on the acoustic.

Perhaps you are coming from a place of far more experience than I am, and please correct me if I'm wrong, but at least that's what I've noticed in my practicing.

I should point out that both statements are true, depending on whether or not you are playing with amplification.

An electric guitar, unplugged, is perhaps the most forgiving variety of guitars, but play it too often unplugged and you'll develop bad habits that are painfully noticeable when plugged in.

I pretty much played acoustics exclusively for a couple of years, only to find out when I picked up my Les Paul that I had developed a lot of 'acoustic-only' bad habits that I had to unlearn. Little things like muting with my fretting hand -- great cheat on an acoustic, but basically acts like a double-tap on an electric.

I am an indifferent player, and shortly after getting my electric, I said to a friend that it was a lie that electrics hide mistakes. He replied "you're not playing with enough distortion"...

Yea, I should have written the disclaimer that it all depends on what you're playing, what kind of amplification, etc. One instance of where electric exposes technical mistakes more is with accidental string bending, like when you're trying to hit an awkward chord, or any chord at all as a beginner. Overall, I'd still go with electric being more forgiving. A sort-of-proof of this is that the set of songs you can play on acoustic is a subset of the songs you can play on electric. Think of a ridiculous Jimi Page solo as being in the electric-only set. Many acoustic songs might not suit electric, but you can still play them with electric. Eh, maybe it's not a proof, but it sounds clever. :)

I personally ended up doing mostly finger-style acoustic with all kinds of weird alternate tunings, so probably nobody should take my word for it.