Stuff that annoys you...

when reading code not written by yourself. For example, I cannot stand it when  people use

if (condition)
    ...
else if (condition)
    ...
else if (condition)
    ...
else if (condition)
    ...
else

instead of the much more readable


if (condition)
    ...
else
    if (condition)
        ...
    else
        if (condition)
            ...
        else
            if (condition)
                ...
            else

>>13
Implicit begin/progn comes at the cost of too many parens, and it is not often useful, especially when writing functional code. Without it you can leave out parens between each branch, like the way arc does it; you only need to add parens if you want a progn (which Clojure and Arc both call (do)).