Rom Manager messed my phone up?

During class last night I saw people post that the nightly 35 gave better battery life, i've been stuck on nightly 18 because it gave me the best battery life compared to all cm4dx nightlies i used...I'm not a huge stickler like some for battery life, but i want my phone to last me throughout the day and no cm4dx release has (yet)...but i'm willing to stick with it because i love the settings...anyways - i downloaded nightly 35 in class and then when i got to my gf's house i told her i was going to play with my phone for like 5 minutes and then i would be done (she doesn't like that i play with my phone "alot") so i started up rom manager and was going to install nightly 35 through rom manager and my phone just froze up and i was like "hmm..thats not good" so i was just watching it and it didn't get past the moto emblem and i just let it sit for like 5 minutes...ended up having to sbfing my phone and all - thank god i've done it plenty of times so i could get my phone back to cm4dx before we went out for the night... has this happened to anyone else?

- sorry for the long story... i want to tell people but i feel like my friends/family will just give me the "you play with your phone too much.." speech...