I usually stay very calm whenever I get a pr, however if it's special I sometimes give a shout or so. I'm usually happy the whole day.
When I got 29.7 for Casualty for TS2 in early 2004, I was very happy. It was a top 5 time and I was ranked fairly low, so it was special. It was in fact the first video I've ever released. There was something before that video though. The day after I got 32.x (maybe it was 33 though) for Casualty, I was going to capture my run with my brother. So after I found the run on the tape, I decided to watch it one more time before rewinding to capture. My brother suddenly rewinded right in the middle of the run and when we were going to capture, it turned out that the run was now damaged. I was very angry and I could've strangled my brother. There was nothing to do about it, so I did what I had to do: playing the level again to improve it on tape. So then after playing the level for three days, I got that 29.7, late in the evening. I screamed ''YES !!!'' and must've shaken like crazy.
Another time was in early 2006. I had nailed my 2nd untied world record the day before and right before I was going to sleep, I decided to play Badass Buspass Impasse for a short time. Wr was a three way tie with 39.0, I was ranked 4th with 39.1, so I was playing for a wr. After about 20 minutes, I got a great run, 20.1 pickup, great boosts. Like 5 seconds before the end, I thought ''this has got to be 39.0''. I ran into the time portal and the timer stopped at 38.7. I was staring in disbelief at the screen when the endscreen with ''New best time!: 0:38.7 secs'' popped. I jumped out of my seat and gave a modest shout because it was at night. Then I stared at the endscreen for some minutes, realizing I had achieved
''The sub 39''. I was shaking until I went to sleep, half an hour afterwards.
The opposite is also possible. I had been playing for hours after passing the wr score for Fight Off the Living Dead and was going to finish the run the day after I started (I paused to sleep and my arms were tired of playing). After my exam, I came home, continued the run and died in half an hour. I signed in on msn and wrote ''It's over'' to FW (since he was the only one that knew I was on a wr run for FOTLD) and at that point the run was over. I was calm, but relieved and satisfied.
One more thing, pd's endscreen music is the most satisfying music to hear after nailing something good. I can listen to it for minutes after a good pr.