Perhaps not irrational, but I don't know. Acrophobia, glossophobia, hydrophobia (only deep water, shallow rivers etc are fine) and monophobia. The fear of heights and deep water came out of nowhere when I was in my early 20s, the other two I've had for much longer. However, I'm going to try and conquer my fear of heights by doing a non-stop lap of the Chester city walls next year, which is where I first realised my acrophobia. Friends and family have offered to sponsor me so I can make a donation to charity, which will be Mind, a cause very close to my heart for the invaluable support they've given me and my loved ones in our times of need.