diff --git a/ClosedXML/Excel/PivotTables/PivotValues/XLPivotValues.cs b/ClosedXML/Excel/PivotTables/PivotValues/XLPivotValues.cs
index ef16caf..e1c4a73 100644
--- a/ClosedXML/Excel/PivotTables/PivotValues/XLPivotValues.cs
+++ b/ClosedXML/Excel/PivotTables/PivotValues/XLPivotValues.cs
@@ -38,7 +38,7 @@
             var pivotValue = new XLPivotValue(sourceName) { CustomName = customName };
             _pivotValues.Add(customName, pivotValue);
 
-            if (_pivotValues.Count > 1 && !this._pivotTable.ColumnLabels.Any(cl => cl.SourceName == XLConstants.PivotTableValuesSentinalLabel) && !this._pivotTable.RowLabels.Any(rl => rl.SourceName == XLConstants.PivotTableValuesSentinalLabel))
+            if (_pivotValues.Count > 1 && this._pivotTable.ColumnLabels.All(cl => cl.SourceName != XLConstants.PivotTableValuesSentinalLabel) && this._pivotTable.RowLabels.All(rl => rl.SourceName != XLConstants.PivotTableValuesSentinalLabel))
                 _pivotTable.ColumnLabels.Add(XLConstants.PivotTableValuesSentinalLabel);
 
             return pivotValue;
diff --git a/ClosedXML/Excel/Tables/XLTable.cs b/ClosedXML/Excel/Tables/XLTable.cs
index 81429f2..b343b51 100644
--- a/ClosedXML/Excel/Tables/XLTable.cs
+++ b/ClosedXML/Excel/Tables/XLTable.cs
@@ -28,7 +28,7 @@
             while (true)
             {
                 string tableName = String.Concat("Table", id);
-                if (!Worksheet.Tables.Any(t => t.Name == tableName))
+                if (Worksheet.Tables.All(t => t.Name != tableName))
                 {
                     Name = tableName;
                     AddToTables(range, addToTables);
@@ -119,7 +119,7 @@
                 Int32 colCount = ColumnCount();
                 for (Int32 i = 1; i <= colCount; i++)
                 {
-                    if (!_fieldNames.Values.Any(f => f.Index == i - 1))
+                    if (_fieldNames.Values.All(f => f.Index != i - 1))
                     {
                         var name = "Column" + i;
 
diff --git a/ClosedXML/Excel/XLWorkbook.cs b/ClosedXML/Excel/XLWorkbook.cs
index ac9e0d7..20ca064 100644
--- a/ClosedXML/Excel/XLWorkbook.cs
+++ b/ClosedXML/Excel/XLWorkbook.cs
@@ -546,7 +546,7 @@
 
         private void checkForWorksheetsPresent()
         {
-            if (Worksheets.Count() == 0)
+            if (!Worksheets.Any())
                 throw new InvalidOperationException("Workbooks need at least one worksheet.");
         }
 
diff --git a/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/Excel/XLWorkbook_Load.cs
index aacb2ab..e5991e1 100644
--- a/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -1248,12 +1248,12 @@
                         var comment = definedName.Comment;
                         if (localSheetId == null)
                         {
-                            if (!NamedRanges.Any(nr => nr.Name == name))
+                            if (NamedRanges.All(nr => nr.Name != name))
                                 (NamedRanges as XLNamedRanges).Add(name, text, comment, true).Visible = visible;
                         }
                         else
                         {
-                            if (!Worksheet(Int32.Parse(localSheetId) + 1).NamedRanges.Any(nr => nr.Name == name))
+                            if (Worksheet(Int32.Parse(localSheetId) + 1).NamedRanges.All(nr => nr.Name != name))
                                 (Worksheet(Int32.Parse(localSheetId) + 1).NamedRanges as XLNamedRanges).Add(name, text, comment, true).Visible = visible;
                         }
                     }
@@ -1729,7 +1729,7 @@
             if (columns == null) return;
 
             var wsDefaultColumn =
-                columns.Elements<Column>().Where(c => c.Max == XLHelper.MaxColumnNumber).FirstOrDefault();
+                columns.Elements<Column>().FirstOrDefault(c => c.Max == XLHelper.MaxColumnNumber);
 
             if (wsDefaultColumn != null && wsDefaultColumn.Width != null)
                 ws.ColumnWidth = wsDefaultColumn.Width - ColumnWidthOffset;
diff --git a/ClosedXML/Excel/XLWorkbook_Save.cs b/ClosedXML/Excel/XLWorkbook_Save.cs
index 3411fea..e4a1a5d 100644
--- a/ClosedXML/Excel/XLWorkbook_Save.cs
+++ b/ClosedXML/Excel/XLWorkbook_Save.cs
@@ -309,10 +309,10 @@
                 }
 
                 // Remove any orphaned references - maybe more types?
-                foreach (var orphan in worksheetPart.Worksheet.OfType<LegacyDrawing>().Where(lg => !worksheetPart.Parts.Any(p => p.RelationshipId == lg.Id)))
+                foreach (var orphan in worksheetPart.Worksheet.OfType<LegacyDrawing>().Where(lg => worksheetPart.Parts.All(p => p.RelationshipId != lg.Id)))
                     worksheetPart.Worksheet.RemoveChild(orphan);
 
-                foreach (var orphan in worksheetPart.Worksheet.OfType<Drawing>().Where(d => !worksheetPart.Parts.Any(p => p.RelationshipId == d.Id)))
+                foreach (var orphan in worksheetPart.Worksheet.OfType<Drawing>().Where(d => worksheetPart.Parts.All(p => p.RelationshipId != d.Id)))
                     worksheetPart.Worksheet.RemoveChild(orphan);
             }
 
@@ -668,7 +668,7 @@
                         rId = xlSheet.RelId;
                 }
 
-                if (!workbook.Sheets.Cast<Sheet>().Any(s => s.Id == rId))
+                if (workbook.Sheets.Cast<Sheet>().All(s => s.Id != rId))
                 {
                     var newSheet = new Sheet
                     {
@@ -2606,7 +2606,7 @@
                 pivotTableDefinition.AppendChild(rowItems);
             }
 
-            if (!pt.ColumnLabels.Any(cl => cl.CustomName != XLConstants.PivotTableValuesSentinalLabel))
+            if (pt.ColumnLabels.All(cl => cl.CustomName == XLConstants.PivotTableValuesSentinalLabel))
             {
                 for (int i = 0; i < pt.Values.Count(); i++)
                 {
@@ -4994,7 +4994,7 @@
             }
 
             var exlst = from c in xlWorksheet.ConditionalFormats where c.ConditionalFormatType == XLConditionalFormatType.DataBar && c.Colors.Count > 1 && typeof(IXLConditionalFormat).IsAssignableFrom(c.GetType()) select c;
-            if (exlst != null && exlst.Count() > 0)
+            if (exlst != null && exlst.Any())
             {
                 if (!worksheetPart.Worksheet.Elements<WorksheetExtensionList>().Any())
                 {
diff --git a/ClosedXML/Utils/OpenXmlHelper.cs b/ClosedXML/Utils/OpenXmlHelper.cs
index 6f0c7a2..950ed19 100644
--- a/ClosedXML/Utils/OpenXmlHelper.cs
+++ b/ClosedXML/Utils/OpenXmlHelper.cs
@@ -11,7 +11,7 @@
 
         public static bool GetBooleanValueAsBool(BooleanValue value, bool defaultValue)
         {
-            return value == null ? defaultValue : value.Value;
+            return value.HasValue ? value.Value : defaultValue;
         }
     }
-}
\ No newline at end of file
+}