Sorry, but I don't have hours and hours to spend documenting bugs, checking to make sure they haven't already been submitted, and checking to see if I might be wasting my time because another version has been released. I've already had to spend too much time trying to figure out how to work around the bugs I've found in the process of trying to get some useful work done.

Knowing that I wouldn't have these problems with Excel, doesn't help; but before Excel was the best, Quattro Pro and Lotus didn't have the bugs LibreOffice Calc has, and they're gone. So for LibreOffice to survive, the top priority needs to be fixing what doesn't work, not adding features or eye candy.

Some of the 9 problems I've found in only 3 sessions are so serious, that any programmer who also uses LibreOffice for serious work would have long since identified and corrected them.

11/15/14: If I move cells with formulas that refer to other cells on that sheet from one sheet to another, the references to those cells that were moved in the cells that were not moved are not updated to show they are now referencing another worksheet, e.g., on Sheet1 enter 12 in A1, 14 in A2, =A1+A2 in A3, =A3*A1 in B3, =B3+E3+A2 in C3, =A2+A1 in D3, =B3-A1 in E3, select and cut B3:C3, select cell K19 on Sheet2 and paste. Note the cell references in cell E3 on Sheet1.

11/16/14: Copying a set of 5 horizontally/vertically merged cells, moving left/up 5 cells and pasting, copies the merged cells properly. Selecting the 5 destination cells left of/above the group being copied and pasting copies the merged cells properly and unmerges the original cells being copied.

11/16/14: If a sheet is displayed so that the left/upper most cell in an active merged cell (group of 5 cells) is left of/above the left-/upper-most column/row displayed, the heavy line around the cell indicating that it is selected disappears. If the merged cell is selected after its left/upper cell is positioned left of/above the left-/upper-most column/row, the heavy line around the cell indicating it is selected is not displayed, and visible the window is not adjusted to make the entire cell visible.

11/16/14: When the input variables on one sheet are updated, the calcualations on that sheet are updated, but the chart on another sheet created by that data is not automatically updated (recalculation must be manually forced on the chart sheet).

11/16/14: When a data range is added to a chart, the only way to correctly add the Range of Name or Y-Values is to select the ranges or to type/correct them in the "Select Range for [Name/Y-Values] of [Data Series Name] Area" dialog box. The ranges can be changed in their Data Ranges dialog box fields, but the changes are not accepted.

11/16/14: Copy and rename a sheet with a chart having:
   Range for Name $[other sheetname].$[H/M/R/W]$57
   Categories $[other sheetname].$C$4:$C$56
   and 4 Ranges for Y-Values $[other sheetname].$[H/M/R/W]$4:$[H/M/R/W]$56
   On the copied sheet manually change $56 in Categories and Ranges for Values to $36 (i.e., show data for 33 years instead of 53). When the changes are made, the chart appears updated, however, when a cell elsewhere on the sheet is selected to force exiting the chart edit mode, the old/unchanged chart is shown, including in page preview, even though the chart is shown correctly again in the edit mode, until the spreadsheet is manually saved.
   
11/18/14: Cell C13 & D13 contain general number 24.09 and text 24.09.13, respectively (European dates dd.mm and dd.mm.yy in a .CSV opened on a US machine). Formula to convert the first dd.mm and the second year to a date would be =DATE(2000+VALUE(RIGHT(D13,2)),MOD(C13,1)*100,INT(C13)), however, for this particular date the formula returns 08/24/13 rather than 09/24/13. Note that:
   =DATE(2000+VALUE(RIGHT(D13,2)),0.09*100,INT(C13)) works
   =DATE(2000+VALUE(RIGHT(D13,2)),C13*100-INT(C13)*100,INT(C13)) works
   =DATE(2000+VALUE(RIGHT(D13,2)),(C13-INT(C13))*100,INT(C13)) does not
   =DATE(2000+VALUE(RIGHT(D13,2)),MOD(C13,1)*100,INT(C13)) does not
   A similar problem occurs with number 7.05 and text 07.05.13 and others, but not all.
   
12/16/14: Name a cell on a worksheet. Deleting a cell in any row/column above/left of that cell, moving cells below/right up/left, respectively causes the cell naming only of all cells below/right of the deleted cell to move as if the entire row/column had been deleted.

12/16/14: If any block of cells is copied to somewhere else on a worksheet, the new copy is selected; however if you want to changed the selected range to copy elewhere, holding down the shift key and pressing the left or up key moves the end of the selection to cell A1, and pressing the down or right key moves end of the selection down or right relative to cell A1.