I too went to the theatre last week and there were two empty seats in front of me. Yippee thought I. Then the show opened and 10 minutes later, in comes Mrs Aggravating, causing everyone to stand up to let her reach her seat in the middle of the row. Then she fusses and fidgets about taking her coat off, then her phone went off and lights up. People either side ask her to switch if off. Five minutes later it goes off again, and up she gets (causing another row of stand ups), leaves the auditorium briefly and returns with her friend, presumably the one who was texting her to say she'd now arrived. Late. Then we get the repeat wave of everyone having to stand up before they both eventually settle down. And all this while the perfomers are in full swing.
If this was you in Row C, Dress Circle, Chicago, Bristol Hippodrome, 25 April, then please don't do it again. It's selfish in the extreme and very rude to both the audience and the performers.