I think celebrating more as Tahir does is better (though not best when over celebrating) than some who don't just celebrate after a wicket and go about their business as if nothing happened. Can't recollect the names but have seen so many of such types in club cricket as well as in internationals. Just makes it feel so boring and as if the wicket was not worth taking at all which I dont think can ever be the case. Even if the wicket taken is the last wicket when still a 100 runs to score, a wicket always gives happiness to a bowler I would think.
Couple of other worst celebrations I can think of is
1) Hassan Ali's bomb blast type of celebration. Given that Pak hasn't had international cricket due to all that is going on in the country related to security, to have someone celebrate as if a bomb has gone off I am not sure is a good idea
2) the Nagin dance of ban players - for some reason it seems very disrespectful to the batsmen, not sure why but it feels that way unlike other types of celebrations..