Because I want it to be nice - I bought new fitted sheet, top sheet, pillow cases etc and a lovely new white bedspread and it all looked so nice and crisp when I put them on and I washed them and now they look like a discarded origami experiment
You need a better iron. Just bought Azure from Phillips (great reviews on Amazon). Under thirty quid and fantastic. Extremely hot and so much steam I have to iron near an open window. I'm 48 so I've had lot of irons in my life. This is absolutely the best I've ever had. I assume you use fabric conditioner as makes ironing easier. I never iron sheets but do iron one side of duvet covers. Sheets crumple as soon as you get into bed.