The first band I was in had a terrible name but we were popular locally and couldn't change as pubs would just advertise us with the original name.
The events leading to the hasty naming involved a group of mates that got together with instruments in someone's kitchen once a week, not a band as such, just having a laugh. We went to the pub one evening to see a band and one guitarist was trying to chat up the barmaid with the old, "Oh yeah, I'm in a band you know", line. It worked so well he got us a booking and she asked the name of the band to put in the diary. We weren't a band and we had no name. He looked around for inspiration and a random bloke was wearing a bobblehat, erm "The Bobblehats" he said, Tw@t. Anyway we had to choose who would play what a get a set together in three weeks. The gig was horrendous and amazing at the same time. I had massive feedback issues for the first half but got it sorted in the break, at the end a bloke came up and congratulated me on my amazing sound in the first half but didn't like what I'd done to it in the second. It was noisy, raucous, and ferocious and people were dancing on tables and anything that would move got dragged out and danced on/broken. We were paid and the banned from ever playing there again. I learnt a lot that night, not least that we were The Bobblehats and the name stuck.
Moral of the story, pick your name wisely, it might haunt you for a long time.