[non123]

I remember I first bought a Java book to learn to program when I was around 15-16. I tried for days but couldn't figure out why the first example program wouldn't work, it was because it wasn't System.out.print1n but System.out.println. In the font the code was written in, I couldn't tell. Because of that it wasn't until at least a year later that I didn't try again.

[dexy]

Exact same thing happened to me when trying to do my first cs problem set. It was some filename that I was sure had a 1 in it but it was an l. It's almost as if courier tries as hard as possible to make the two look the same.

[jleader]

Courier was intended to look like a traditional typewriter font. For many decades, most typewriters didn't have a key for 1 (one), you were supposed to use the lower-case l (ell) instead.

Teletypes did have a one key, probably because they were all-uppercase, so there wasn't a lowercase ell available.

[manish_gill]

Happened to me while learning C++. endl or end1...so confused.