Everything is a matrix, that's horrific (especially the Nx1 vs 1xN ambiguity which pops up all the time). No default argument values (and until recently, no support for keyword args, though they have a bad version now), meaning half your code lines are input parsing. Forced vectorization does the opposite of making code clean, it makes complicated code a lovecraftian mess (unlike Julia, which lets you vectorize efficiently at the top level.) Every function must live in an m-file(#$@&%*!) Everything in your path is in scope :(

The varargin/varargout/nargout mess, with outputs specified in the signature line, instead of proper return statements.

Also, for a language that requires vectorization for performance, there should really be a proper `map`, instead of the mess that is `arrayfun`/`cellfun`/`structfun`. Their arrays are super-limited, no mixed-element arrays (use cell-arrays!), so `[3, [4,5,6], 7]` is just concatenated, while `[3, [4;5;6], 7]` errors (and check out what `[3, "hello", 7]` does(!) or `[3, 'hello', 7]`)

Poor support for integers, 2 is a double(!), and `int8(3)/int8(2) == int8(2)` (yikes.)

Their OOP is actually not that bad, though it's slow. And their graphics system is pretty ok.

Also annoying: now you have two types of strings, old-fashioned 'abc', and new-fangled "abc", which are very different, and sort-of, half-way work together. Though I think moving to the new strings is actually a good move, but painful now.