I love and use LibreOffice, but I do find Calc much harder to work with than Excel. PivotTables, sortable lists with locked headings and sort-buttons, even simply setting print area were all harder for me to get used to and implement on Calc than Excel.
I persist because I like the goal of FOSS, and it's "good enough" for my usage, I can definitely understand when people show frustrations - especially power users that have worked with MS Office for decades.