I walked up Djouce in County Wicklow today. I had a plastic bag and gloves with me, so I picked up the litter on the way down.
Well done
@Brendan Burgess. You shouldn't have to do it but great that you did.
I also regularly pick up litter on my walks - lately mainly Phoenix Park and Bull Island but sometimes further afield. Mainly dog excrement which someone has gone to the bother of bagging only to throw it on the ground, sweet wrappers, coffee cups, takeaway food packaging, bottles/cans (made a few bob off those

), tissues as you mention, nappies, and other miscellaneous stuff. Condoms and sanitary towels also turn up but I tend not to pick them up as I don't usually have gloves. It's shocking how irresponsible some people are.
I do this in my own area and environs too but it's usually a pointless exercise elsewhere going closer to Dublin city centre because that would be a full time job.
A few people have complimented me and it's nice to get some positive feedback rather than the more common funny looks

but it would be nicer if people just didn't litter so much.
(And, no - as I was asked recently - that
wasn't me on Liveline recently about the dog excrement in the Phoenix Park

).