diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index 4ee1efa595167c..55b09fbd1cf91a 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -203,7 +203,7 @@ similar(   a::AbstractArray, T, dims::Dims)   = Array(T, dims)
 
 function reshape(a::AbstractArray, dims::Dims)
     if prod(dims) != length(a)
-        throw(ArgumentError("dimensions must be consistent with array size"))
+        throw(ArgumentError("dimensions must be consistent with array size (expected $(length(a)), got $(prod(dims)))"))
     end
     copy!(similar(a, dims), a)
 end
@@ -326,8 +326,8 @@ function copy!{R,S}(B::AbstractVecOrMat{R}, ir_dest::Range{Int}, jr_dest::Range{
                     A::AbstractVecOrMat{S}, ir_src::Range{Int}, jr_src::Range{Int})
     if length(ir_dest) != length(ir_src) || length(jr_dest) != length(jr_src)
         length(ir_dest) != length(ir_src) &&
-            throw(ArgumentError("source ($(length(ir_src))) and destination ($(length(ir_dest))) must have same size"))
-        throw(ArgumentError("source ($(length(jr_src))) and destination ($(length(jr_dest))) must have same size"))
+            throw(ArgumentError("source and destination must have same size (got $(length(ir_src)) and $(length(ir_dest)))"))
+        throw(ArgumentError("source and destination must have same size (got $(length(jr_src)) and $(length(jr_dest)))"))
     end
     checkbounds(B, ir_dest, jr_dest)
     checkbounds(A, ir_src, jr_src)
@@ -347,8 +347,8 @@ function copy_transpose!{R,S}(B::AbstractVecOrMat{R}, ir_dest::Range{Int}, jr_de
                               A::AbstractVecOrMat{S}, ir_src::Range{Int}, jr_src::Range{Int})
     if length(ir_dest) != length(jr_src) || length(jr_dest) != length(ir_src)
         length(ir_dest) != length(jr_src) &&
-            throw(ArgumentError("source ($(length(ir_src))) and destination ($(length(ir_dest))) must have same size"))
-        throw(ArgumentError("source ($(length(jr_src))) and destination ($(length(jr_dest))) must have same size"))
+            throw(ArgumentError("source and destination must have same size (got $(length(jr_src)) and $(length(ir_dest)))"))
+        throw(ArgumentError("source and destination must have same size (got $(length(ir_src)) and $(length(jr_dest)))"))
     end
     checkbounds(B, ir_dest, jr_dest)
     checkbounds(A, ir_src, jr_src)
@@ -710,7 +710,7 @@ function hcat{T}(A::AbstractVecOrMat{T}...)
     for j = 1:nargs
         Aj = A[j]
         if size(Aj, 1) != nrows
-            throw(ArgumentError("number of rows of A[$j] ($(size(Aj,1))) must match $nrows"))
+            throw(ArgumentError("number of rows of arrays must match (got $(map(x->size(x,1), A)))"))
         end
         dense &= isa(Aj,Array)
         nd = ndims(Aj)
@@ -742,7 +742,7 @@ function vcat{T}(A::AbstractMatrix{T}...)
     ncols = size(A[1], 2)
     for j = 2:nargs
         if size(A[j], 2) != ncols
-            throw(ArgumentError("number of columns of A[$j] ($(size(A[j],2))) must match $ncols"))
+            throw(ArgumentError("number of columns of arrays must match (got $(map(x->size(x,2), A)))"))
         end
     end
     B = similar(full(A[1]), nrows, ncols)
@@ -783,7 +783,7 @@ function cat_t(catdims, typeC::Type, X...)
             currentdim = (d <= ndimsX[i] ? size(X[i],d) : 1)
             if dims2cat[d] == 0
                 dimsC[d] == currentdim ||
-                    throw(DimensionMismatch("mismatch in dimension $(d)"))
+                    throw(DimensionMismatch("mismatch in dimension $(d) (expected $currentdim, got $(dimsC[d]))"))
             else
                 dimsC[d] += currentdim
                 catsizes[i,dims2cat[d]] = currentdim
@@ -840,7 +840,7 @@ function hvcat(nbc::Integer, as...)
     # nbc = # of block columns
     n = length(as)
     mod(n,nbc) != 0 &&
-        throw(ArgumentError("all rows must have the same number of block columns ($nbc)"))
+        throw(ArgumentError("number of arrays $n is not a multiple of the requested number of block columns $nbc"))
     nbr = div(n,nbc)
     hvcat(ntuple(i->nbc, nbr), as...)
 end
@@ -871,16 +871,16 @@ function hvcat{T}(rows::Tuple{Vararg{Int}}, as::AbstractMatrix{T}...)
             Aj = as[a+j-1]
             szj = size(Aj,2)
             if size(Aj,1) != szi
-                throw(ArgumentError("mismatched height in block row $(i)"))
+                throw(ArgumentError("mismatched height in block row $(i) (expected $szi, got $(size(Aj,1)))"))
             end
             if c-1+szj > nc
-                throw(ArgumentError("block row $(i) has mismatched number of columns: $(c-1+szj) $nc"))
+                throw(ArgumentError("block row $(i) has mismatched number of columns (expected $nc, got $(c-1+szj))"))
             end
             out[r:r-1+szi, c:c-1+szj] = Aj
             c += szj
         end
         if c != nc+1
-            throw(ArgumentError("block row $(i) has mismatched number of columns $(c-1) $nc"))
+            throw(ArgumentError("block row $(i) has mismatched number of columns (expected $nc, got $(c-1))"))
         end
         r += szi
         a += rows[i]
@@ -896,12 +896,12 @@ function hvcat{T<:Number}(rows::Tuple{Vararg{Int}}, xs::T...)
 
     a = Array(T, nr, nc)
     if length(a) != length(xs)
-        throw(ArgumentError("argument count does not match specified shape $(length(a)) != $(length(xs))"))
+        throw(ArgumentError("argument count does not match specified shape (expected $(length(a)), got $(length(xs)))"))
     end
     k = 1
     @inbounds for i=1:nr
         if nc != rows[i]
-            throw(ArgumentError("row $(i) has mismatched number of columns $(rows[i]) != $nc"))
+            throw(ArgumentError("row $(i) has mismatched number of columns (expected $nc, got $(rows[i]))"))
         end
         for j=1:nc
             a[i,j] = xs[k]
@@ -928,7 +928,7 @@ function typed_hvcat(T::Type, rows::Tuple{Vararg{Int}}, xs::Number...)
     nc = rows[1]
     for i = 2:nr
         if nc != rows[i]
-            throw(ArgumentError("row $(i) has mismatched number of columns $(rows[i]) != $nc"))
+            throw(ArgumentError("row $(i) has mismatched number of columns (expected $nc, got $(rows[i]))"))
         end
     end
     len = length(xs)