tbf, when I title emails. they are always found pretty quick. when I search for emails crated by others, I can never find them and it's usually related to people using non descriptive, clear and concise wording related to clients names, tickets, work etc...

how I would write an email subject..

client name - project reference 12345 | alt ref numbers

how others would write that same title

abbreviated client name noone uses...project work

or

from last week's meeting...

or similar crap like that... people are HORRIBLE with documentation..