public static class ExceptionExtensions
{
  private static void ExplainException(
    Exception exception, int level, StringBuilder builder)
  {
    if (exception == null) return;

    builder.AppendFormat(
      "{0}@{1}: {2}\n{3}\n",
      exception.GetType().GetFriendlyName(),
      level,
      exception.Message,
      exception.StackTrace);

    var aggregate = exception as AggregateException;
    var exceptions =
      aggregate != null
      ? aggregate.InnerExceptions
      : Enumerable.Repeat(exception.InnerException, 1);

    foreach (var inner in exceptions)
      ExplainException(inner, level + 1, builder);
  }
}